"I wanted you to know that I am having a horrible screen glitches after installing 10.7.2 on my mac pro. I have upgraded my mac pro over the years to keep it current. I have a Mac Pro 1.1. It is modified with new 5770 GPU, dual quad-core CPU's and 16 gb of ram.

I have included a link to a forum that talks about this very subject. I am sure that I am not the only one with this issue. (I've not read all posts in that thread, but ADC displays seem a common item in problem reports. (A DVI to ADC adapter used of course.))
Please help spread the word, write about this problem. Hopefully we can get apple to listen!
https://discussions.apple.com/message/16333480#16333480
(Thread titled "My desktop screen keeps flashing".)
Thank you, John W."

Here's a post from that thread with a tip, which someone else also said helped.

"So after a day of the flickering, and trying everything to solve it, I have fixed mine at least for now.

I took the monitor cable from the Apple DVI/ADC adaptor out my MacPRO while it is on, right out of the video card. Then I waited about 10 seconds and plugged it back into the video card.

Problem solved. I have not rebooted, no sleep mode and I have not logged out since doing this, so I do not know if this fixed it for good. (FYI: Some have noted this didn't survive a reboot/logout, etc)

So far it is back to it's good old self. Let me know if this works for anyone else.
Thanks, Jeff M."

The reply just below that from another affected owner said "Well that is just odd. That worked for me as well." (Maybe that forces a display re-detection?) Hopefully that helps others as well. (I was about to ask if the usual update TS tips were tried, zap pram/nvram, check for corrupted prefs/files, reinstall w/download updater, etc.)

Replies from other (Upgraded) Early Mac Pro owners running 10.7.2: (later added/updated first)
(FYI on ADC Screen Flashing: I had a 2010 Mac Pro owner w/ATI 5870 card and adapted ADC display report the same screen flashing problem in 10.7.2. And same (temporary) fix - disconnect/reconnect. He had opened a case with Apple and later wrote: "Apple called me today to let me know that their engineers have reproduced the issue in-house on the 20" and 23" ADC LCD displays... and that it's been escalated, to be fixed in a future release")

(More Info added Oct. 16th)
"Vintage 2006 1,1 Quad 3GHz (two dual-core cpus), 12GB with an (ATI) 5870 connected to three 30" monitors. NO display problems at all with 10.7.2.
(he later wrote with more info:)
Stock dual 3.0 GHz CPUs, 12GB RAM. Boot ROM MP11.005C.B08.
OWC Mercury Extreme SSD 200 GB Boot drive, four additional internal 2 TB drives.

(Details on Video card and displays used)

ATI 5870 (Apple shipped) w/ROM Revision 113-C0780C-194
1 - 30 Apple Cinema Display (2006) native DVI connection
1 - 30 inch HP LP3065 (2008) via Apple Mini Displayport to Dual-Link DVI
1 - 30 inch HP ZR30W (2011) via Apple Mini Displayport to Dual-Link DVI

Also briefly swapped the ACD with a 2011 Apple 27" MDP monitor without problems - but liked having three 30" monitors so bought the HP ZR30W instead.

No display problems at all. Just waiting for the 2011 models to replace by almost 5.5 year old machine. Still plenty fast, but system feels stressed and the add-on bluetooth dongle is terrible (tried four different brands, all lousy).
-Michael K. M.D"

"Mac Pro 1,1 (2006), 2.66GHz, 8GB RAM, ATI Radeon HD 4870 (Apple original),
Samsung 27in and original (*) Apple Cinema Display, OS X 10.7.2.
No display issues other than rare minor screen artifacts.
(* I asked about Apple Cinema display, as the first was a DVI 22in model, the 2nd Cinema model (intro'd in summer 2000) used an ADC port.)
Good point, forgot about that. It's a 22" ADC model from 2001, connected to the ATI 4870 via Mini DisplayPort to DVI Adapter -> DVI to ADC Adapter. USB ports on the display died long ago.
-Bill E."

I had an original DVI 22in Cinema display (1600x1024 native rez) many years ago. It was a refurb/return w/stuck (blue) pixels close to the center. Still have a spare (NIB) AC adapter for it here somewhere.

"Macpro 1,1 8GB ram (4x2GB), Radeon 4870 (PC flashed), Samsung SyncMaster 740BF using DVI running with 10.7.2 with absolutely no problems.
Best regards, Julien"

"My MacPro 1,1 had no trouble with the 10.7.2 update. I have restarted and tested sleep several times, there is no video corruption. My video card is a Radeon 5870 but it is a flashed Sapphire PC card, not an Apple (shipped) card. It is connected to an I-INC 28" monitor with an HDMI cable.
-David C."

"Early Mac Pro w/Upgrades (Quad-Core CPUs, Video card, etc) and 10.7.2
Mac Pro 1,1 (2006) modded w/dual 1.86GHz Quad-Core CPUs. Video card Nvidia 8800GT. No (EFI 2,1) firmware upgrade still 1,1. 8GB of Ram. No issues/
Regards, Robert B."

"Early Mac Pro with upgrades and Lion
I upgraded yesterday (Oct 12), and haven't had any problems. The 4870 is not apple (shipped) original, it is a flashed pc card, (article here on doing that) - otherwise no other modifications done to the machine.

One thing that I did notice, Since upgrading to Lion, my mac would only startup into the lion recovery partition without any intervention. I could hold down option and boot into anything, or select windows (bootcamp) in startup disk, but if I selected my lion startup disk, it was back to recovery. Once there I would do a restart and I would get my lion startup disk without holding option.

With all the updates yesterday, it now seems back to normal. I've started up 3 or 4 times, and it boots directly to my lion disk.
-Rob W.

Model Name: Mac Pro
Model Identifier: MacPro1,1
Processor Name: Dual-Core Intel Xeon
Processor Speed: 3 GHz
Number of Processors: 2
Total Number of Cores: 4
L2 Cache (per Processor): 4 MB
Memory: 13 GB
Bus Speed: 1.33 GHz
Boot ROM Version: MP11.005C.B08
SMC Version (system): 1.7f10

ATI Radeon HD 4870:
Bus: PCIe
Slot: Slot-1
PCIe Lane Width: x16
VRAM (Total): 1024 MB
Vendor: ATI (0x1002)
Device ID: 0x9440
Revision ID: 0x0000
ROM Revision: 113-B7710C-176
EFI Driver Version: 01.00.318

Displays:
L226WT:
Resolution: 1680 x 1050 @ 60 Hz
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Apple Studio Display:
Resolution: 1280 x 1024
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: Off
Online: Yes
Rotation: Supported "

"I've had screen flickering problems on and off with my 1,1 Mac Pro since I installed the (officially unsupported) Mac ATI 4780 upgrade video card.
I have a Gateway 24" monitor on the DVI output and a Cinema Display 24in on the Display Port.

I think around 10.6.5 the Gateway display (only) would flicker on and off, or have static, or have horizontal lines. I discovered that I could routinely fix it by setting it to 800x600 and then going back up to full resolution. This is easy to do because the Cinema Display is set as the primary monitor so I can see the display drop down.

Then around 10.6 to 10.6.8 the problem went away.
It came back in 10.7.2 (not 10.7 or 10.7.1)

But I just do the same resolution switch and it fixes almost every time.
Sometimes I have to do twice.
Note that it has to be a big resolution switch. Just going down one level or two is not enough.
Also, if I do it really fast sometimes that requires a slower redo and then it works.
Sounds similar to the pull the DVI plug fix someone mentioned. Maybe if you only have one monitor you could do an Apple Script to mimic this?
-Edward G."

"10.7.2 Flashing problem - I have the same thing and the "fix" works too but not through a logout or restart.
Mac Pro 2009 2.8 Quad, Radeon HD5770, ADC connector to Cinema Display (original) 23"
-MRE"

5770 doesn't have an ADC port (ADC is 28VDC display power + DVI in one connector) so I assume he's using a DVI to ADC adapter that provides ext power for ADC display. (5770 has 2 MDP and 1 dual-link DVI IIRC.)

"Thought I'd send in a positive report for you as I saw the request.
MacPro 2,1 (2007 w/Dual 3GHz Quad-Core CPUs) with 5770 card bought from Apple. (I had a 4770 (4870?) from Hong Kong and it never worked for me). No flicker on 10.7.2.
Was worried when I read the site (apple forum thread).
I've already been running for a day including sleep / wake.
All fine. In fact, everything is "snappier" with 10.7.2.
Only other upgrade I have is a Crucial C300 SSD as my boot drive.
Manually re-enabled Trim from: http://digitaldj.net/2011/07/21/trim-enabler-for-lion/
-Aled
(Displays/Graphics card info follows)

Cinema HD 30 inch - DVI
Dell 20 inch - Mini DP to DVI adaptor.

Processor 2 x 3 GHz Quad-Core Intel Xeon
Model Identifier: MacPro2,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 3 GHz
Memory: 16GB 667 MHz DDR2 FB-DIMM
Graphics: ATI Radeon HD 5770 1024 MB
Software: Mac OS X Lion 10.7.2 (11C74)

ATI Radeon HD 5770:
ROM Revision: 113-C0160C-155
EFI Driver Version: 01.00.436
Displays:
DELL 2001FP:
Resolution: 1600 x 1200 @ 60 Hz
Pixel Depth: 32-Bit Color (ARGB8888) Mirror: Off
Online: Yes
Rotation: Supported

Cinema HD:
Resolution: 2560 x 1600
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported"

I'd asked for details in the post but almost no info in this reply:

Early Mac Pro with upgrades and Lion
"Standard config. No issues
Kind Regards, John "