(Since these are retail cards (not flashed with mac rom), there's no boot screen until the OS/driver loads. For instance if booting with Option key to select startup disc. Also don't use FileVault. (You could select a different Startup Disk in macOS, but IIRC only 10.12.6 and later have native driver support for RX 580.) Check your RX580 card for the required power cable - most need a Dual 6-pin (for Mac Pro connectors) to 8-pin (video card connector) power cable. It's good to have a second card like an OEM Mac Nvidia GT120 that uses no Aux power. (Also some macOS upgrade/installers (like High Sierra) required an OEM Mac graphics card installed, so keep your original Mac card on hand.) The Sapphire Pulse Radeon RX 580 is also one of the recommended models for use as an eGPU with macOS 10.13.4 (or later). See Apple's article on Using an external graphics processor with your Mac that lists supported Thunderbolt 3 chassis & graphics cards.)

macOS Mojave: On Sept. 24th, 2018 Apple released MacOS Mojave and posted a new support article Install macOS 10.14 Mojave on Mac Pro (Mid 2010 and Mid 2012), that mentions having macOS 10.13.6 installed first, (without FileVault enabled) and a list of compatible graphics cards, with a note about no startup video displayed from some 3rd party graphics cards (i.e. cards without a Mac ROM). Also don't forget that firmware updates won't work if your startup disk is a RAID drive, so use an onboard SATA boot drive for updates/upgrades.

" These specific third-party graphics cards are Metal-capable and compatible with macOS Mojave on Mac Pro (Mid 2010) and Mac Pro (Mid 2012):

• MSI Gaming Radeon RX 560 128-bit 4GB GDRR5
• SAPPHIRE Radeon PULSE RX 580 8GB GDDR5
• SAPPHIRE Radeon HD 7950 Mac Edition
• NVIDIA Quadro K5000 for Mac
• NVIDIA GeForce GTX 680 Mac Edition

Some other third-party graphics cards* based on the following AMD GPU families might also be compatible with macOS Mojave on Mac Pro (Mid 2010) and Mac Pro (Mid 2012):

• AMD Radeon RX 560
• AMD Radeon RX 570
• AMD Radeon RX 580
• AMD Radeon Pro WX 7100
• AMD Radeon RX Vega 56
• AMD Radeon RX Vega 64
• AMD Radeon Pro WX 9100
• AMD Radeon Frontier Edition

If the graphics card in your Mac Pro isn't listed above, you need to install one that's compatible with macOS Mojave. If you need additional help, contact Apple Support.

Turn off File Vault, then install macOS Mojave
Many (most) third-party graphics cards won't show anything on the display when macOS Mojave is starting up, including the Apple logo and startup progress bar. (emphasis mine.) As a result, you can't log in to a system that uses FileVault, choose a different startup disk before your Mac boots into macOS, or perform some hardware diagnostics.

You'll need to turn off File Vault and then follow the steps to download and install macOS Mojave on your Mac Pro.

* Third-party graphics cards vary, so you should check with the vendor of your specific graphics card for compatibility details."

Radeon RX 580 owner reports on MacOS 10.14/10.14.1 Mojave Installs (later added first)
(See notes on No Filevault & proper power cable. Sapphire cards are preferred, not XFX.)
If you upgraded to Mojave from 10.13.6 OK, please include your Mac Pro bootrom version. Thanks.
(macOS 10.14.1 EFI/bootrom was 140.0.0.0.0 that added boot NVMe support on Mac Pro 5,1.
I'm told as of macOS 10.14.6, the latest Mac Pro 5,1 EFI/bootrom is 144.0.0.0.)
(I've not heard of any recent SMC updates, but if you notice one let me know.)
And remember no FileVault, and upgrade from a macOS 10.13.6 volume. Most RX580 cards need Dual 6-pin (Mac Pro connections) to 8-Pin (video card) power cable. As noted in Apple's upgrading Mac Pro to Mojave guide - you must have 10.13.6 installed before upgrading to Mojave.

The following report is on macOS 10.14.1 with later firmware (bootrom) than with 10.14.

"Sapphire Nitro+ Special Edition RX 580 in Mac Pro 2012 - macOS Mojave 10.14.1
Date: 11/01/2018
I've got a Mac Pro 5,1 (Mid 2012) with a 3.46 GHz 6-Core Xeon. It was running macOS Sierra 10.12.6. The boot drive is a RAID Level 0 (Stripe) from two Samsung 850 EVO SSDs, each mounted on a separate SeriTek i6G card. The RAID uses SoftRAID Lite drivers. My old video card was a Radeon 5770 that shipped with most of the Mid 2012 Mac Pros.

In order to update the OS to Mojave, I bought a Sapphire Nitro+ RX 580 8GB Special Edition card.

But before I could install the new hardware, I first had to update to macOS High Sierra.
(Apple's article on Mojave installs on Mac Pros notes having 10.13.6 before upgrading. And remember firmware updates won't work if booting from a RAID drive - use an onboard SATA boot drive for the upgrade/update.)
The RAID boot volume became the first challenge - neither High Sierra nor Mojave 'want' to install on a RAID. (IIRC, Apple's firmware updates won't install from a boot RAID volume.-M)  So I carved out a new partition on one of my spinning-platter hard drives that was roughly the size of my boot volume. I cloned my boot volume to the partition with Carbon Copy Cloner, then booted to the clone. Updated the clone to High Sierra, then cloned the drive back to my original RAID boot volume. Booted that into High Sierra-success!

Next, i installed the Sapphire Nitro+ RX 580 card. For powering it, I followed advice from your site, and used a dual mini 6-pin to 8-pin cable-purchased on Amazon. Removal of the old 5770 and installation of the Sapphire RX 580 were straightforward.

But when I booted to High Sierra with the RX 580, I got a loud fan noise. Opening up the Mac Pro case, I could see that the problem was the USB-C PCIe card immediately above the RX 580. The Nitro+ is a monster-sized card, and even though both PCIe cards were installed properly in their slots, the USB-C card was being hit whenever the RX 580 fan moved.

Taking heed of the advice from Ladd on your site (earlier report) who used a popsicle stick to shim between two cards, I tried to use stick-on 3M rubber pads to push the two cards apart. Unfortunately I could not get that to work-even shimmed the Nitro+ fan would vibrate against the adjacent card. So for the moment I've had to remove the USB-C card in order to use the RX 580 without obstructing its fan. I'll revisit that problem later, but for now I would advise anyone that has every single PCIe slot filled in their Mac Pro 5,1 and who wants an RX 580, that the Sapphire Nitro+ models might be a challenge, and they should stick with the Sapphire Pulse models, or another less-beefy RX 580 version.

After getting the RX 580 working well in High Sierra, I cloned my boot drive to the backup volume on hard drive, booted to the clone, then powered down. Then I physically disconnected all volumes except the clone from the Mac Pro, booted to High Sierra, updated the clone drive to Mojave, powered down. I reconnected all my drives, rebooted to the clone, and then used Carbon Copy Cloner to clone BACK from the clone to my RAID boot volume. Success!

Both the High Sierra and the Mojave installers required firmware updates to my Mac Pro. After the High Sierra firmware update, System Information showed Boot ROM Version: of MP51.0089.B00. After the Mojave (10.14.1) firmware update, System information showed Boot ROM Version of 140.0.0.0.0. (Previous 10.14.0 had bootrom 138.0.0.0.0. Version 140.0.0.0.0 adds boot NVMe support on these Mac Pros - a big plus for PCIe card NVMe SSDs. See this Review of NVMe SSD PCIe card in a Mac Pro with 140.0.0.0 firmware.)

System Info/Bootrom after 10.13.6 Install

System Info/Bootrom after 10.14.1 Install

Benchmarks comparing the Radeon 5770 and the Radeon RX 580 showed improvements, of course. But some improvements were much more extreme than others.

For example, Cinebench R15 OpenGL results barely budged.

Radeon 5770 OpenGL frames per second: 63.15

Radeon RX 580 OpenGL frames per second: 69.21
-or a 9.6% bump. Yawn.

While the Batman: Arkham City built-in benchmarks showed a noticeable but modest improvement:

Radeon 5770 frame rates: Min: 27, Max: 47, Average: 36

Radeon RX 580 frame rates: Min: 29, Max: 117, Average: 58
- so the average FPS is 1.6 x.

Other benchmarks, like LuxMark v3.1, showed significant improvements.

Radeon 5770 LuxMark v3.1 results: 1851

Radeon RX 580 LuxMark v3.1 results: 16371
- that's 8.8 x.

GFXBench GL showed good improvements in offscreen results.

Radeon 5770 GFXBench GL T-Rex Offscreen: 180.95 FPS

Radeon RX 580 GFXBench GL T-Rex Offscreen: 605.34 FPS
- that's 3.3 x.

Best Regards, Trevor"

Thanks Trevor, appreciate the detailed report.

Reports below were before macOS 10.14.1 was released.

"Mojave (10.14) Upgrade Mac Pro 5,1
Date: 10/28/2018
I've got a Mac Pro 5,1 with 3.33 GHz 6-Core Xeon, 16GB RAM, Radeon HD 7950 (Sapphire) GPU. Have had little issues with OS updates on this machine, but after reading issues with Mojave I was a little leery. Finally backed up may boot drive and took the plunge today.

After a shutdown and reboot the install started. Took under an hour and was updating from High Sierra and boot drive was already converted to APFS. Came up, no fuss, no muss. Accounts all good and everything running fine. No issues with Wi-Fi, but checked before I started and I didn't have a /etc/sysctl.conf file. (That file if present has caused Wi-FI/Ethernet problems. Fix is renaming (or deleting it) and rebooting.)

No issues, so kind of a boring report, but wanted a report that didn't seem like the sky was falling on this update. Great site and very useful over the years.
Thx, Bruce"

Thanks Bruce. (If you later change to a Radeon RX580 8GB video card, let me know.)

"Mac Pro RX580 upgrade and Mojave (10.14)
Date: 10/11/2018 (late posting here)
Thought I'd add to the data... I've a 2012 Mac Pro, which was running a 5xxx ATI card. Took the plunge on no boot screen and purchased a stock Sapphire Pulse RX580 8GB from a local retailer here in NZ - was lucky to be able to find the exact model.

With High Sierra fully patched - and once I had the relevant power cables - I got the card going. There's no boot screen of course, so it's a leap of faith; I timed the machine booting with the old card so I had some idea of when to expect the chime, when to see USB device lights flash etc. as a check. High Sierra identified the card completely accurately as the RX580, but System Information only reported a link speed of 2.5GT/sec.

I didn't bother swapping cards to install Mojave. Since https://support.apple.com/en-us/HT208898 doesn't mention it, I didn't. Yes, the machine needed a firmware update; I just crossed my fingers and let it run blind. It only took a few minutes before rebooting back into High Sierra; I now have the same rather odd Boot ROM version as others report - 138.0.0.0.0. The main Mojave installation took ages, but it's now running fine.

Interestingly, under Mojave the card is now reported in System Information as running at 5GT/sec. I don't know which OS is telling the truth but a brief run of benchmarks doesn't show any obvious changes with the new OS.
TTFN, Andrew"

Thanks Andrew.

"Mojave 10.14 / Mac 5,1 / Sapphire Pulse Radeon RX 580 4GB DDR5
Date: 10/05/2018 (late posting here)
After Apple published the list of compatible cards, I found one, I thought, and ordered it. My error was that I ordered the 4GB (VRAM) model instead of the listed 8GB model. There wasn't much that I could do but wait. (Same GPU so it will be compatible.-M)

It arrived, then I looked for some installation notes, and found that I needed to get new power cables for it. The available videos showed using two mini 6 pin to 6 pin cables, then into a dual 6 pin to an 8 pin. I couldn't find those at any single source, but I did find a dual mini 6 to 8 in a single assembly from modDIY.com in China. That came this morning (4-5 days after order). (Aux Power cables are mentioned/linked in some early reports way down the page.-M)

I installed the RX 580 (I had to move up one of my USB cards to get overhead clearance). My Mac came up (10.13.6) and all seemed fine. I proceeded with the 10.14 update; was advised that a firmware update was needed and I followed the instructions. That fared well; and the screen came back ready to proceed with the Mohave installation. A couple of inputs later and the install was on.

There were a few long periods of dark screens (monitors reported no signal), but eventually, a progress bar appeared. There was another period where the progress bar seemed not to be advancing, but I fought my impatient concerns and kept my hands in my pocket (figuratively). The progress bar advised another 35 minutes to go. I came back to check a couple of times and then it was asking for my password. I entered, and all came to life as I expected.

Since I had disconnected all ports at the outset, I shut down, reconnected everything, and restarted. All looks good, sort of.

My original video card (5770) fed two monitors via mini display ports to DVI and a third by direct DVI. With the new card, two of the monitors are HDMI connected. I'm finding that text isn't as sharp as previously. I have to work on video adjustments to see what improvements I can make. (Try to match the output resolution to the display's native resolution, at least as close as possible. A 1:1 match will be the sharpest (no scaling, which will soften the image).-M)

Anyway, the key reason for submitting this is to advise that the 4GB RX 580 seems to be working fine, despite not being on the list.

My MacPro is mid-2010, 3.2 GHz Quad-core Xeon / 16GB RAM, with a 500GB SSD as my startup disk. The other 3 bays have a total of 11TB (one for iTunes (4TB), one is my Home Drive (also 4TB), and a 3TB for backup (one of three rotating Time Machine drives. CCC backs up daily my iTunes drive to another 6TB external drive.
Regards, Brian"

Thanks Brian.

"Mac Pro 5.1 Mojave (10.14) update (Sapphire Radeon RX 580 Nitro+)
I thought I'd send a short update to my earlier June 26th report (with High Sierra) concerning the installation of a Sapphire Radeon RX 580 Nitro+ (8GB) in a Mac Pro 5.1 (mid 2010)

After seeing the positive feedback on your site from other users of the 580 RX series graphics cards, I decided to go ahead with the update to Mojave.

The firmware update and OS update proceeded without difficulty with the Nitro+ installed. Starting OS was High Sierra 10.13.6. (as specified by Apple)

Info of my system

Thanks for providing such a good forum for sharing this kind of information.
- Peter W."

Thanks Peter, appreciate the follow-up (and details in the previous one).

"Mac Pro 4,1 with Radeon RX 580 updated to Mojave (10.14)
Date: 9/29/2018
2009 Mac Pro 4,1 flashed to 5,1 bootrom, 2 x 3.33 GHz Quad-Core Intel Xeon, 26GB RAM, with non-Mac flashed Sapphire Radeon Pulse 580 8GB mounted in slot 1, Crucial 512GB SSD with High Sierra mounted on OWC PCI board immediately above the Radeon, four 4TB spinning drives in the drive bays.

Radeon card is a snug fit under the OWC PCI board; I had to put a popsicle stick on top of the Radeon board between the two fans to lift the OWC board slightly so as to not just barely hit the fans.

Updated the Crucial SSD from High Sierra to Mojave; it took at least an hour, possibly as much as two. (I was in and out of the room); when the screensaver kicked in, I knew the update was ready for the next step.

Firmware update went fine with the Radeon 580 installed. Boot ROM went from MP51.0084.B00 to 138.0.0.0.0.

I did not disconnect anything from the back of the Mac Pro, but nothing was turned on other than the three monitors. I dismounted all hard drives from the Desktop when starting the upgrade process; no idea if they were accessed during the multiple restarts.

Only the Crucial SSD was updated to APFS; none of the spinning drives were.

Thanks to the previous reporters for their upgrade experiences. It gave me the confidence to attempt the OS upgrade and also that I didn't have to remove the GPU for the upgrade! :-)

I've only been running Mojave now for about 10 minutes longer than it took me to type this up; everything is running smoothly, but can't say I've done much exploring yet.
- Ladd"

Thanks Ladd.

This report includes a note about boot problems with unsigned Extensions.

"Mojave (10.14) with Mac Pro 2009 (FW hacked from 4,1 to 5,1) and MSI Radeon RX 580
Date: 09/29/2018
Quick summary: Works, with some patience.
Updated in place from 10.13.6, had to update firmware first (Boot ROM went from MP51.0084.B00 to 138.0.0.0.0). The two issues I had were video-related and extensions.

Video-wise, it seemed to not properly set up video in a few cases when I was debugging. Since the card doesn't support EFI, the monitors just sleep like its connected but no signal. In a few cases, the monitors came out of sleep, but were still dark. I replugged the connections to trigger a refresh and it displayed fine. This was important with a few cases I booted to rescue mode, when I wanted to verify it was even doing anything.

The biggest annoyance was it wouldn't boot fully after install. Screen stays dark and asleep for hours. If I press shift to try to wake it, nothing. If I press enter, it beeps like "invalid key", as if it's booted enough to say "Wrong". When I tried with my old video card, it would boot to about 95% progress and stop, with the same key behavior (ergo same situation, just now with visual). At this point, you must remember how to boot safe-mode (hold Shift). It came up fine.
I then moved all unsigned Extensions, as reported by System Information (both /Library and /System/Library) to another harmless folder, and rebooted just fine. All good now, just dark screen after chime for a minute or two as expected.

Going on 10 year old machine, still running the latest OS.
- Lycestra"

Thanks for including notes/tips on the problems you saw.

"2012 Mac Pro with RX 580 and Mojave 10.14 install (Follow-up)
Date: 9/28/2018
Just an update - I was encouraged to read others had success with their Mac Pros (w/RX580 only) and suspected my issue with the firmware update might be resolvable by removing peripherals. (I have a TON connected and had failed to disconnect them earlier when trying to get the firmware update to take.) Just FYI I was running 10.13.6.

After disconnecting peripherals, I was able to get the firmware update to install with the RX580 (blank screen, but worked fine). Mojave installed in the same fashion, blank screen during boot but otherwise no issues. Nice to not have to swap video cards.
(I hoped this would be true after Apple revised that Mojave support doc in August - saying some model cards like this without Mac ROM were supported. They also expanded the list of cards in their Install Mojave on 2010-12 Mac Pro article.-M)

Just thought I'd let you know. I'll keep you posted if I flag any issues going forward. :)
- Matt"

Thanks for the follow-up. From the earlier comment I wasn't sure you had actually tried to update the firmware with only the RX580 installed, since with High Sierra the update required a mac ROM card. And I think the lack of boot video until the setup starts (which can take a long time) may also have some aborting the update. (Apple mentions that in the install guide, I made that note red text in above copy.)

"Mojave (10.14) Clean Install with RX 580 Nitro
Date: 09/25/2018
I updated to 10.14 (Clean Install) my Mac Pro 2009 flashed to 5,1 last night (New Zealand Time).

I knew you won't see the apple logo when you press power button. The solution is you have to select the target disk as normal boot first and restart your computer. Don't freak out with blank screen, it will take a while till you will see the setup screen.

Then you can erase disk on "Disk Utility", and then I started to install 10.14 Mojave, same as usual for previous macOS.
(So the firmware update went OK with only RX580 installed? What is your Mac Pro bootrom version after the 10.14 upgrade?-M.)

The issue that I found is Wi-Fi Hardware showed not installed and it's completely die.
(See below. If no Wi-Fi, maybe no Ethernet also.-M)
The rest runs smooth at the moment.
- Anya"

Update: Some users with Wi-Fi (or Ethernet) problems said a post on renaming /etc/sysctl.conf file helped. (Original post/tip I was later removed at Apple's forum. Link now has a copy.)
IIRC, Some Broadcom cards (BCM94321MC ?) are not supported in Sierra and later macOS versions. I think BCM94322MC is still supported in Mojave. (Also heard Atheros 9380 not supported in Mojave.) And there's Mojave threads (here and here) where other Mac model owners, including a 2013 Mac Pro have reported no Wi-Fi hardware after the 10.14.0 upgrade. (.0 Major OS upgrades have always had bugs. I wonder if the 10.14.1 update will help this. It was out in beta the day after 10.14 was released.) In the past (before Mojave), some suggest resetting NVRAM, SMC, refresh network prefs, clear caches, etc. but that won't help a lack of chipset support.

Below report updated 9/27 to add confirmation (screenshot) of BootRom version after 10.14 upgrade, and that the upgrade from 10.13.6 to 10.14 worked with only his Sapphire Radeon RX 580 card installed.

"2009 Mac Pro and Mojave 10.14 (also notes on High Sierra Install)
Date: 09/25/2018 (updated 9/27 AM - more info/2nd Mac Pro upgrade)

I'm the owner of a 2009 Mac Pro flashed to a 2010 (5,1) with a Sapphire Pulse Radeon RX 580 8GD5. Last week I upgraded from Sierra to High Sierra in anticipation of updating to Mojave today. I'm happy to say that things have gone smoothly with just a couple small wrinkles.

The first wrinkle occurred while updating from Sierra to High Sierra. I had to put in my original OEM nVidia GT120 in order to run the firmware update included with the High Sierra install. This firmware updates the Boot ROM version to MP51.0089.B00 as seen in the Hardware section of System Report from About This Mac.

Once this firmware update was applied I installed High Sierra and applied all the updates from the App Store. I then put my Radeon RX 580 back in and things worked well over the last week.

The second wrinkle happened during the Mojave upgrade. The Mojave installer wanted to run another firmware update so I dutifully swapped out my Radeon for my OEM GT120. Upon running the installer again I got the notice that my machine needed a Metal compatible video card. It turns out there was no need to swap the Radeon for the GT120 in to run this Mojave firmware update.

Once I put my Radeon (RX 580) back in I was able to run the firmware update w/o any problems and then followed the normal update process for installing Mojave. The Boot ROM Version was 138.0.0.0.0 according to the Hardware section of system report from About This Mac.
(Odd boot rom version, normally has MP51 prefix. Can you confirm?-M)

No problem. Since my initial report I've also updated my machine at home, which is nearly identical to my work Mac Pro (it has a Xeon W3565 3.2GHz upgrade). They both use the same Fusion drive arrangement and Radeon RX 580.
I can confirm the Boot ROM Version is 138.0.0.0.0 after a fresh reboot of both Mac Pro systems under 10.14.

(his original comments sent on 9/25 follow)

Mojave took about an hour to fully install, and afterward I was greeted by the setup screens and finally the beautiful Mojave Dark Mode desktop.

One other note for those interested. Several years ago I made my own Fusion drive from an OWC 256GB SSD and a 2GB Western Digital HDD. The update from High Sierra to Mojave also changed my boot drive from HFS+ to APFS. While it's too early to know for sure, so far things are running smooth and I've seen no issue with the update.

(Your Partition map type shows "unknown", was it that way before the APFS/Fusion drive conversion?)

Unfortunately I didn't think to check either system's Fusion drive partition map type before updating from 10.13.6 to 10.14, so I have no way of knowing what it looked like before the Mojave update.

I did check the file system on my home machine's Fusion drive before the Mojave update and it was HFS+. I would guess the partition map type was GPT, but that's only a guess. I don't have any other Fusion drives to compare that are still on High Sierra.

(I want to confirm that the Mojave 10.14 upgrade (and firmware update) from your 10.13.6 install worked with -only- the Sapphire Radeon RX 580 card installed.-M)

When I ran the Mojave installer with my GT120 card in place at work, the installer wouldn't run the firmware update. I just got a message saying Mojave required a Mac with a Metal compatible video card. As you note, I was running the Mojave installer on 10.13.6 machines. The firmware update on my home machine also ran fine with the Radeon RX 580 installed. (emphasis mine.) I didn't bother swapping my GT120 on my home machine during the Mojave update.

Let me know if you have any further questions. So far I haven't had any issues with either machine.
- Jim W."

Thanks Jim - appreciate the details.

"Mojave (10.14) and RX 580
Date: 09/26/2018 - (updated 10/1/2018)
I've been running the Sapphire RX580 Pulse 8GB card in my upgraded 2009 Mac Pro 4.1 (originally an 8-core 2.26GHz but now flashed to be a 5.1 and a 12-Core 3.06GHz).

I've been using the card first with High Sierra and now Mojave. Once you get used to the lack of a boot screen (less problematic than I imagined it might be - there is a Mac Pro Boot ROM update required again for Mojave and unlike the one with High Sierra this was even possible with the RX580 installed) it really is a great choice for these machines, reasonable power consumption, never gets loud and good 1440p performance in games (the only title I can't run is Mafia 3 but that appears to be it not liking dual CPU machines as single socket owners can run it). Thanks to Apple using the same card in their development box for eGPUs and the same chipset in the iMac it is really well supported.

I had the card on back order for many months after I first read about it being an option (this was after the iMac 5K with the same chipset was announced) because of the all the cryptocurrency miners.

The main reason at the time for me upgrading was for the game F1 2017. I had purchased a Mac ROM flashed EVGA GTX680 4GB for the previous game F1 2016 (after F1 2016 didn't support the Radeon 7950 Mac Edition I had been using since 2014 (itself an upgrade form the OEM 4870 and then kit 5870 Apple offered). The GTX680 worked very well for that game (but I did find the fan on the Nvidia card noisy under heavy load).

When F1 2017 arrived it wasn't stable with the GTX680. With Apple only making Macs with AMD and Intel graphics since 2012 Nvidia support is only via web drivers for newer cards and with the OpenGL to Metal transition and some titles supporting one card and the next titles not getting a suitable GPU has been like ping pong!

With the long wait on the RX580 I sold the flashed GTX680 and got a Mac EFI flashed R9 280X - this uses the same chipset as the D700 in the 2013 Mac Pro cylinders so was well supported but it needed a 6-pin and 8-pin power cable and technically can draw more total power than the 2009-2012 Mac Pro models support for a GPU. An 8-pin to 6-pin adaptor was included with that and apart from the load lights on my UPS being maxed out when the card was worked hard I never actually had a problem myself but some folks have had machines power off with these under the most extreme loads.

(added clarification on the UPS load comment)
It was only the R9 280X that used to max out the UPS as that card had the highest max power consumption of all the cards I've owned. The RX 580 has a much lower draw and I'm only using a single 1440p display. Power draw and noise is also why I stuck to the 95W X5675 CPUs as Apple only officially used 130W in the single CPU models which have a larger heat sink for the one chip.

My UPS is an APC 1000VA and really only there to allow a safe shutdown in case of a power cut. I picked this capacity as it was the largest without a fan.

(Some early RX 580 reports have notes on power usage, but nothing extensive. (I was concerned about one report that tried using all 5 card outputs at once, but only short term I think.) The only comment on a shutdown so far was the RX 580 "Nitro+ Special Edition" overclocked (6-pin + 8-pin card) report in a Mac Pro with Dual 6-core 3.46GHz CPUs when running FurMark benchmark, solved he said by cable changes with his Nitro+ SE card which has both an 8-pin and 6-pin connector instead of a single 8-pin. (Not sure I'd have done that.) To date, no other reports of problems like that, but YMMV. Maxed out CPUs (Higher speed Duals), drives, RAM, PCI cards, etc. can also tax the PS and I wish they had provided for 8-pin connectors and more power. I realize the dual 6 pin and spec limits of the Mac Pro towers are not impressive (300W spec on PCIe cards IIRC, although good design practice should have some extra margin). With some high end cards, an external power supply really is required. (And I understand the concern about a single cable 6-pin to 8-pin adapter, but the standard RX580 uses both Mac Pro 6-pin to the card's single 8-Pin connector.) In the past I have heard of shutdowns, including overheating problems from broken Northbridge heat sink retainers. I still wonder if the reader that was using a GTX-285 and ATI 4870 Card (both use two 6-pin aux power connections) back in 2010 ever had a failure. I posted some system power usage (from my UPS LCD display) with my Dual 2.66GHz (8 core) Mac Pro at various tasks (including Quake4 timedemo, Motion, Cinebench) vs idle in 2009 when I did the GTX-285 review (vs ATI 4870, GT120). Of course that's an old card, but it wasn't a lightweight. I saw a max total system power draw on my dual 2.66GHz X5550s with the GTX 285 of 405W. Anandtech's tests of the RX-580 shows total system power draw Max (during Crysis 3 test) of 330W with the Sapphire Nitro+ (overclocked) model. 360W with the PowerColor Red Devil 580. Their PC test system details are at this page bottom - Intel Core i7-4960X @ 4.2GHz, ASRock Fatal1ty X79 Pro motherboard, 750GB SSD, 32GB RAM, Corsair AX1200i PS, Windows 10 Pro. They have another page on multi-monitor usage.-M.)

With the delays I actually almost cancelled the RX580 a few times but when it did arrive I ended up with an amazing price thanks to the Amazon pre-order lowest price deal they run.

The RX580 has a single 8-pin power connector and the Pulse version doesn't come with cables so you need a Y cable i.e. 2 x 6-pins on the Mac to 1 x 8 pin on the card (You risk overloading with a single 6 to 8). (I agree.-M) These are not so common a cable put I found one on eBay from Hong Kong I think. (Some of the early RX 580 reports below (before Mojave) include notes on Aux power cables, with links to Amazon.)

As long as you have a version of MacOS new enough to have the RX580 drivers built-in it really is plug and play. (macOS 10.12.6 and later have RX 580 driver support.) The card is a slightly tighter fit (the PCI-E slot above mine is empty but you might struggle with a large card there).

Certainly it really should keep me going until I can see what Apple finally come up with for the next Mac Pro design. I never thought nearly a decade ago I'd have so much value out of this machine that is for sure!
Best regards, Matthew"

Thanks Matthew.
(For years I've wished Apple would offer an affordable minitower, using standard form factor Power Supply, motherboard, Graphics card, Thunderbolt ports, socketed CPU, M.2 slots. A simple design, upgradeable workhorse (not a closed work of art). Using standard parts would make it easier (and cheaper) for them to upgrade over time to keep it fresh, and for owners to upgrade/repair. Gave up on it happening though. Hopefully the 'modular Mac Pro' will at least have user replaceable parts.)

"Mojave (10.14) with RX 580
Date: 09/25/2018
Hi everyone, I'm using my Sapphire Pulse RX580 8 GB with my MacPro mid-2012 (MacPro 5,1) since beta release of Mojave in June 2018 without any problems.

Installing Mojave over High Sierra using Nvidia GeForce GT640 2 GB (Flashed for mac) / Removing this card after Mojave installation.
As expected, no boot screen with the RX580 GPU. Installing the final release of Mojave Monday, September 24th, 2018.
Everything works flawlessly with two screens (DP and HMDI outputs)
Regards, Michel T."

Thanks Michel.

Earlier reports and comments below are from before macOS Mojave was released.
(Some 2009 Mac Pro 4,1 owners had flashed their bootrom to 5,1 for support of later macOS versions.)

(August 2018) Apple's prepare for macOS Mojave page has this note on 2010-12 Mac Pro Compatibility.
(Below info is from August post - see above for later/updated listing.)

"Mac Pro models introduced in late 2013, plus mid 2010 or mid 2012 models with recommended Metal-capable graphics processor, including MSI Gaming Radeon RX 560 and Sapphire Radeon PULSE RX 580"

Earlier notes and reports on Sapphire Radeon Pulse (and Nitro+) RX 580 cards in Mac Pros follow.

macOS Mojave *Beta* install Problems
(Update - see later (non-beta) Mojave install reports above.)

"Mojave Beta install problems on 2010-12 Mac Pros (wait for public (non-beta) release)
I have a 2010 Mac Pro 5,1 64GB Ram with an RX 580 (which I bought after reading the installation successes on your blog) but have not been able to install Mojave beta on my system. I have tried everything but a clean install and may eventually do so, but my prime request of you is if you are getting any feedback on people with the 2010 users either having success or failure.

(Reply: I've seen posts on problems with Mojave Beta installs like this (under 6th report below), but Apple's Installing macOS Mojave on 2010-2012 Mac Pros article lists the Sapphire RX 580 card as supported. (Have macOS 10.13.6 already installed first, no FileVault.) See reports above confirming this - including firmware updates applied with only the Radeon RX 580 card installed.-M)

I also have a glitch, probably with the card, which causes the screen to blink without any apparent reason. No help from the cardmaker - they tried to say the card would not work on a mac.
thanks."

Reports below are with macOS High Sierra and macOS Sierra

6th report, added June 29th, 2018. (Nitro+ card, running macOS 10.13.5.)
(Earlier reports below from April 30th, April 20th, March 2nd, Feb. 19th & Feb. 2nd.)

"Another Mac Pro upgrade Sapphire Radeon RX 580
After reading the upgrade reports on this site, I decided to go ahead with a similar upgrade, since the fan was failing on my original Radeon HD5870 graphics. The model graphics card that I installed is the Sapphire Radeon RX 580 Nitro+ (8GB) so it's a model that is slightly different from the other upgrade reports. (Most are Sapphire Pulse, but there's a Nitro+ Special Edition card report below, with card pictures.) I'm running a Mac Pro 5.1 with dual six-core x5675 Xeons, and MacOS 10.13.5.

macOS 10.13.5 System Info (shows Apple Metal is supported)

Also, great hint from one of the previous reports for using just the 8-pin power connector on the RX580 (and a dual 6-Pin female to 8-Pin male cable). So far everything appears to be functioning very well, but to date, I've only tried two monitors.

The next challenge will be upgrading (if possible) to Mac OS 10.14 Mojave (with metal graphics). Apparently, not sure for Mac Pro 5.1, even with graphics supporting metal.
-Peter"

".... What i was told and what worked for me was if you have a 7950 and it boots pre-high sierra with the switch in 1 position, move the switch to the other position before trying to install. High Sierra (yup it's got a switch on the side). (See link above.) Or it won't install.
Don't ask me why - as Grant bennett alder said it probably has to do with the firmware install and update, which is built into the installer and you can't get around. Alternatively, you could dust out your card, install High sierra, then after It has installed, try it with the new card...
- John B.

5th report, added April 30th.

"Another successful Radeon RX 580 upgrade report
Based on the reports on this site, I decided to pull the pin on a Sapphire Pulse Radeon RX 580 8GB card. I am running a Mac Pro 5,1, 12 core, with dual Intel x5675 Xeons. I had been running a Radeon 7950 which was flashed for Mac. While I had fine results with that card, I have been wanting a 3rd monitor, and my 7950 would only support two, as it was a PC version that had been flashed for the Mac. I have not yet connected the third monitor, but monitors 1 and 2 are working fine with the new card. I had to do absolutely no configuration to get it working in OS 10.12.6, but it does show incorrectly as an R9.

It did not show a Mac boot screen until partway through the boot-up process, but this was to be expected. I bought the card off eBay from a non-mining user for $310. He claimed he had under 30 hours on it.

Performance numbers are very good. I hit 53 and change fps in Cinebench. My Geekbench multi core score improved to over 20,000 for the first time. The compute benchmark OpenCL, with the card showing as an AMD Radeon HD Ellesmere Prototype hit 140000.

I suspect adding the 3rd monitor will present no issues. I am currently using 1 monitor in a display port and 1 in HDMI. I do not do anything requiring 4K work, so I only have have 1080p monitors. But the 3rd screen will greatly increase my workflow in music production, so I am quite pleased.
-Phil"

Fourth report, added April 20th. (Earlier reports below on March 2nd, Feb. 19th & Feb. 2nd.)

Sapphire Radeon RX 580 Nitro+ Special Edition in a Mac Pro (5,1)
Last time I was playing with Radeon HD 7970 (R9 280X) on a Mac Pro (2,1) and later on I moved the card to my new Mac Pro (5,1) 12-core 3.46GHz where it served flawlessly and now it's retired as I bought a fancy looking Sapphire Radeon RX 580 Nitro+ Special Edition (the blue one). That particular edition is the fastest version as it's factory overclocked (1430 MHz).

Sapphire Radeon RX 580 Nitro+ Special Edition Card/Installed

I can confirm that there are no compatibility issues (apart from the missing boot screen) and the card is recognised as "Radeon RX 580 8129 MB". There are no sleep problems either, everything works fine on the latest High Sierra (10.13.4).

However, I have a very useful hint for anyone who considers this card. After the install everything seemed fine but after some heavy testing I had the safety shutdown situation when running the notorious FurMark benchmark. The card was connected with the same power cables as my HD 7970 (one 6-pin to 6-pin and the other 6-pin to 8-pin). That worked for years without any problem on the old card. So, I thought that there is not enough power for this card on AUX 6-pin connectors and I bought SATA to PCIe adapter to pull additional power from the optical bay.

However, that was not necessary! The problem was that for some reason this card is not using 6-pin and 8-pin power inputs in a balanced manner. So, two separate cables are not the solution. What you have to do is to completely ignore 6-pin input on the card and use only 8-pin with a splitter to 2 x 6-pin on the motherboard. And voila! Everything works smooth!
(I'd be leery of just using only the 8-pin connector on the card, but let me know if you see any problems long-term.-M.)

I measured the power consumption with Marcel Bresink's Hardware Monitor and the card is idling at only 7.4W on PCIe slot and around 10 - 15W per PCIe AUX lines A and B.
Then, I pushed the card very hard with the FurMark test and it passed the benchmark flawlessly. The consumption was 85-95W at AUX lines and 50-65W on PCIe slot. So, everything seems within specifications that we expect and I guess it's reasonably safe. The card is also very silent in normal use, almost mute if compared to GTX 980 (in my other Mac Pro).

In the end, I can only comment that those Mac Pro towers are the best Macs ever built. It's also silly that, when upgraded, this 9 years old machine is *faster* than the fastest and super expensive current Mac Pro Tube and even faster than entry models of iMac Pro. I hope Apple will come to senses with (7,1).
Best, Davor.

Thanks Davor. How's the performance vs your Radeon HD 7970? (Previous reports were on Sapphire Pulse RX580 8GB ($360 or so). Your Nitro+ SE is a bit more expensive? I saw appx $410 street price?) BTW: From your comments, Hardware Monitor works in 10.13.4? (v5.55 released April 18th, but the Hardware Monitor page doesn't list High Sierra support. He posted a notice last April about Apple and software like HM.)

Third Report, from March 2nd (Sapphire Pulse RX 580 8GB)

"Another Successful Radeon RX 580 Report (Mac Pro 5,1)
(Native driver support in macOS 10.12.6 and later.)
Just letting you know I was enthused to read about the stock Sapphire Pulse 8GB Radeon 580s working natively on Mac Pro 5,1 machines so I decided to upgrade. I have a decked out mid-2012 Mac Pro 5,1 with 64GB of RAM and a 1GB 5870 that I've used for years. It was long in the tooth for doing any serious high-res production work, though most of my archive and personal stuff was on it along with a lifetime of drives connected which always kept me from moving to the newer hardware... 3 RAID arrays, all 4 HD slots with larger SSDs + a OWC SSD PCI card for the boot volume, a bunch of pro audio gear and a smattering of USB volumes for 3rd-tier backup and portability. SO much TLC went into this rig over the years... I was excited to breathe new life into it!

In addition to snagging the dual-6-pin -> 8pin power cable (thanks for that info), I went to the local Micro Center here in PA and picked up one of the Sapphire Pulse 8GB 580s right off the shelf for $360 bucks - took it home, plugged it in and it worked a treat! Along with the card, I snagged a Samsung 4K 28" display (UE510) on Amazon for ~200 bucks to compliment it and I'm running a Apple Cinema Display 27" + the 4K + my Commercial Panasonic Plasma (720p) as a reference monitor and it's absolutely smoking fast. I run the 4K display at 2560x1440 to match the Cinema Display but it will easily run at its 3840x2160 native resolution.

(Samsung display options)

Max Resolutions from the Sapphire PULSE Radeon™ RX 580 8GD5 page specs.
(Card has DVI-D, 2 HDMI 2.0b and 2 DisplayPort 1.4 Ports)

So, I'm using the DVI and 2 DisplayPort connectors for my 3 displays but I still have 2 open HDMI ports at my disposal. Awesome.

(But can you use all 5 of those ports simultaneously? Many cards have limits.)
The tech specs for this particular card (http://pulse.sapphiretech.com/en/580-8.html) says the HDMI ports are 2.0b and it supports 5 outputs max (so I'm supposing all ports can be used simultaneously). I'll root around for a spare couple of HDMI ports and connect the 2 outputs to the extra 2 HDMI inputs on the Samsung to confirm when I have some spare time this week :) I'll let you know how it goes.
(he later wrote)
Just confirming that I can use all five (5) ports on the RX580 simultaneously. Hooked up another display and a projector today alongside the 4K display, Cinema Display and my Panasonic plasma. No problems at all. :)
(Let me know if you continue to use all 5 ports. That likely increases power usage and wonder if it will be a problem long term in the Mac Pro.-M)

(Running 10.12.6 or High Sierra? The System Info on Metal makes me think 10.13.x?)
I am running macOS 10.13.3 High Sierra, fully up to date with the OS.

No issues at all, card was fully recognized plug-n-play (see pics below), and it's seriously quiet and cool most of the time - much quieter than the 5870 as far as I can tell. Metal acceleration in the various apps that support it, along with multicore support makes my old Pro feel like a brand new machine. The only issue I had during the install was cramming the relatively thick chassis of the 580 next to my OWC Mercury Accelsior S in slot 2, which I use for my SSD boot volume. The screws from the OWC card were rubbing up against the fan blades on the 580 fan assembly, so I stuck a small adhesive rubber 'foot' on the casing between the fans of the 580 to push the OWC card away from the blades. Problem solved.

(A retail card w/o Mac rom, so no boot screen. I.E. Booting with Option key to select startup disc.)
I just confirmed - you were right on, I get no video when Option-booting. :/ Glad I kept my 5870 around but I put it into an old 2009 Mac Pro for my son, so I'll need to rob it if it ever becomes an issue. LOL

System Info (shows Apple Metal is supported)

Anyhow - thanks again, and always, for the awesome resource you have at the site. I still reflexively check it most days. :)
Blessings and take care!
-Matt"

Thanks Matt.

Second report from Feb. 19th follows, including comparison to GTX 1050 ti 4GB.

" After reading the report from a previous reader (below) who had good results installing the Sapphire Pulse Radeon RX 580 8GD5 I took the plunge and got a similar deal at CDW for $365 (apparently there was a slight discount for shipping to a corporate address). This card replaced an un-flashed EVGA GTX1050ti using the nVidia Web driver. The Radeon is also un-flashed, just install and make sure to supply auxiliary power to the card using 8-pin to dual 6-pin adapters(*).

Mac Pro System Info
I've got a mid-2009 Mac Pro flashed to a 2010 (5,1) with an upgraded Xeon W3565 3.2GHz 4 core with 32GB ram, macOS 10.12.6 My display is a Dell U2518D running at 2560 x 1440 over HDMI (native).

Before disabling and uninstalling the nVidia driver, cuda support, and removing the GTX1050ti card I ran a few benchmarks. I then installed the Sapphire Radeon RX 580 and re-ran the same benchmarks.

GeekBench 4.2.2 Scores
Here are the results from GeekBench 4.2.2 for Mac OS X x86

GTX1050ti 4GB      OpenCL  71013
Radeon RX 580 8GB  OpenCL 134126

GTX1050ti 4GB      Metal  80267
Radeon RX 580 8GB  Metal 133196

Unigine Valley Benchmark
I don't use this machine for gaming but thought others might be interested in the results of the Unigine Valley Benchmarks.

Settings used for Unigine Valley Benchmark 1.0 Basic (OpenGL)
- Resolution = 1280 x 720
- Anti-Aliasing = 4x
- Gamma = 1.0
- Full Screen
- Ambient Occlusion
- Volumetric Shadows
- Motion Blur
- Vsync
- FPS Counter

GTX 1050ti 4GB    FPS: 22.3 / 48.6 / 62.1 (min / avg / max), score = 2035
Radeon RX 580 8GB FPS: 23.6 / 54.6 / 61.9 (min / avg / max), score = 2284

I didn't notice any significant differences in image quality between these two video cards with the Unigine benchmark.

As one would expect, CPU benchmarks didn't change:
- Single-Core Score = 2792 / 2787 (GTX / Radeon)
- Multi-Core Score = 9370 / 9362 (GTX / Radeon)

BruceX FCP-X benchmark
One other benchmark I only ran on the Radeon is the BruceX FCP-X benchmark. (www.fcp.co/forum/hardware/18250-brucex-try-this-new-final-cut-pro-x-benchmark)

Results averaged over 3 trials exporting as Pro Res 422 to an OWC 1TB SSD, 14.7 seconds. One trial writing to a WD 2TB HD wasn't much longer, about 17 seconds.

Other Notes
So far the card has been very quiet - my WD USB Time Machine external USB backup drive is much more audible than the Radeon. FCP-X, Aperture, Photoshop and After Effects CS5 all feel more responsive.

Let me know if you have any questions about my setup or tests. Thanks for maintaining a great Mac resource!
- Jim.

(*) Auxiliary power cables required.

Two of these - PCI-e Power Cable for Mac G5 nVidia ATI Video Card
www.amazon.com/gp/product/B002UR1654/

One of these - GutsParker Dual 6-Pin Female to 8-Pin Male Cable Black
www.amazon.com/gp/product/B01N3T6C2KM "

The first report follows (Later reports above)

Jman sent word he finally received his Radeon RX 580 8GB card for his Mac Pro 5,1. (Unlike the Radeon R9 280X he previously used, the RX 580 isn't a flashed card.)

"I just got my brand new Pulse Radeon RX 580 8GB video card from a company out of Chicago called CDW. (Computer Discount Warehouse?) The card cost me about $390 with the tax and shipping. I think I got lucky because many of these cards are selling for $500+. (Above retail, due to demand from crypto miners at the time.)
(I assume it's the Sapphire Pulse Radeon RX 580 8GD5. As of August 14th, 2018, Amazon has the Sapphire Pulse Radeon RX 580 8GB for $279.99, but prices can change over time.)

The Pulse Radeon RX 580 8GB works on the Mac Pro 2009-2012 OOTB. (IIRC macOS 10.12.6 and later.) The drivers were built into Sierra & High Sierra. It is essential (IMHO) to use the SwitchResX app to set your Resolution to the desired 4k or 5k monitors, which (in my case) is scaled at 2560X1440@ 60hz. (He's using an LG 32UD59-B 4K 32in Display, scaled due to the menu text size at 3840x2160 native rez.)

In the About this Mac in Sierra 10.12.6 it will show up as an AMD R9 xxx 8192 MB. In High Sierra you will see the full name correctly. There are no problems at start-up. You will see a brief start-up screen and then right to your log-in. It's great and fast.
(Also shows as "Metal Supported")

I don't have a lot of ways to measure this cards performance, but Cinebench R15 is giving me almost 66fps, and Geek Bench 4 OpenCL Score is 134379. That is up from 107000 when using the Radeon R9 280X 3GB card. This card is in the ballpark of the GeForce GTX 1070 Ti. Just as fast as the GeForce Video Card on my Mac in many ways.
(Having native driver support is a plus, where Nvidia's web drivers need updates for each macOS update, although Nvidia has been pretty quick to post web driver updates. Nvidia also has CUDA support, but personally I don't have experience with it.-M)

Interesting upgrade and a very pleasant surprise.

(I asked to confirm it wasn't flashed.)
This card was right out of the box and not flashed.
The Pulse Radeon RX 580 was a card that Apple approved for the developers for Beta testing Sierra and High Sierra. For one reason or the other this card just works. Obviously, the drivers are there. I cannot guarantee that any other Radeon 580 card (such as, Nitro) will work OOTB on a Mac. I did a lot of research to make sure I was buying a Sapphire Pulse Radeon RX 580 8GB video card that would work OOTB on a Mac.

I can't say how much of the start up I am seeing, since I have an SSD Drive. My start up is really fast. Then, the log-in comes up.
[macOS 10.12.6 and later has driver support for this card but since these are not flashed cards (no mac rom) - no boot screen if using the "Option" Key at startup correct? (To select a boot volume.)]
To switch start up drives you have to use start up in preferences. I don't believe the option key works with these cards. But they sure are great video cards!

This card has performed perfectly over the last 48 hours. I know there are quite a few Mac Pro owners using this card. It's a great gaming card.

(he later wrote)
In Cinebench there's only about 1 FPS difference between this card and the R9 280X. However, under certain circumstances the RX 580 will far exceed the R9 280X. This is a gaming card and a card for Digital Video Editing and Rendering.

If you know anyone that wants a Radeon R9 280X 3GB card (flashed) and perfect for 4K monitors, let me know. It's $250 with cables included and (CONUS) shipping. I also have the (Mac) ATI Radeon HD 5770 1GB for $150 (CONUS) shipping included (Sold).

After a month of use, no problems and as your latest report confirms, these cards are VERY quiet, except at start up when the fans rev up. I'm truly happy with the purchase and I see others have benefited from my testing of the card.
-Jman"