"CPU upgrade report - Mac Pro 2008
Been quite a few delays between upgrading my son's mac mini and finally able to upgrade my Mac Pro this week. Of note, there are very few upgrade notes for the 2008 Mac Pro (3,1 model) to be found. Plenty for for 2006 and 2009+ but a real dearth for the 2008. In fact, your site has the only one I found.
I bought a matched pair of 3.2GHZ Xeon X5482 quad-core CPUs off ebay for $495 which is the fastest this Mac can take (It cannot use the 5492s). (Ref: Intel X5482 CPU info.) I've thrown my quad 2.8s on craigslist for $250 for the pair but no hits yet.
You can follow most of the 2006 Mac Pro upgrade notes/youtube videos but there are differences. Specifically:
- The memory cage has four screws instead of two. No big deal as they are obvious.
- The tricky screw is in the fan assembly. The 2006 and 2008 both have the upper screw but the 2008 also has a hidden screw that is not visible unless you look inside the rim of the fan assembly after the processor cover is removed.
- The CPUs are not oriented identically. The bottom CPU's placement is rotated 90 degrees. Again no big deal but should be noted as the mechanisms can tangle if both are open at once.
I used Artic Silver 5 and followed its directions which differ from Apple's. Apple recommends covering the CPU cap with paste liberally (I have the 2006 tech manual) which is not advised by Silver Ice. Considering the issues Apple has had with the overuse of paste on the Macbook Pros I went with Silver Ice's method which is an even line most of the way across the cap which expands to an oval when compressed. Also, in the videos that I saw many of these people were sloppy with the paste and even touched the CPU cap and heat sink with their fingers which is beyond wrong.
Anyway, upgrade went fine and my system has been running as silent as before with no real difference in heat out the back either for 24 hrs a day for a week. Current temps are: 75 F ambient, CPU A: heatsink: 93 F, CPU: 102 F; CPU B: heatsink: 96 F, CPU: 102 F. (Idle temps, and not core temps I assume. Temperature Monitor used?) Memory temps are high at 132 to 156 F. (FBDimms the 2006-08 Mac Pros use can run even hotter. They have an appx 4GHz (IIRC) serial/parallel chip ('AMB' - Advanced Memory Buffer). Some readers reported 80+°C/180+°F FBDimm temps on an older page here on Mac Pro FBDIMM ram. OK if proper heatsinks used but some FBDimms early on didn't.)
It's OWC RAM (I've used them for a decade and buy all my RAM from them) with heat spreaders and lifetime warranty so I'm set if a problem occurs.
Overall a great upgrade that just took the right timing on ebay.
best regards, Wolf"
