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macrumors newbie
Original poster
Apr 20, 2011
- Since both Mac Pro 1,1 and 3,1 are classified as model A1186 does that mean the power supplies are compatible? Can a working power supply from a 2006 model go into a 2008 model and work okay?

- Also, can I take the RAM from my 2006 Mac Pro and put into the 2008 model? I've read conflicting answers on this topic so I'd love to know something more concrete.

- Additionally the CPUs for the two models are of the same socket type so will 1,1 CPUs work in a 3,1? Again, I've read conflicting answers on this topic so does it work or not?

Thanks in advance for any and all constructive feedback!


macrumors 6502
Jun 20, 2014
United States
The 1,1 and 3,1 power supplies are not the same, they have completely different cable plugs.

The 2,1 and 3,1 I'm about 95% sure are the same, but I havent done a swap to make 100% sure.
[doublepost=1489520909][/doublepost]The 54xx series cpu's that are used in the 3,1 will NOT work in a 1,1 or 2,1.
I tried already, installed a set of 5410 cpu's in a 2,1 as a test, and no workee.

The 3,1 can use the slower 667 memory from the 1,1/2,1 it will stay at 667 instead of the correct 800mhz speed for the 3,1.
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macrumors newbie
Jan 29, 2017
Short answer regarding the PSU compatibility between the 1,1 and 3,1, should *air quotes* work fine ether way. Read all of owbp's link above, the 1,1 PSU driving my Pro's 3,1 guts with a Nvidia 750ti works fine.

However, unless you have a free PSU from the other model kicking around to use it may be best to just replace what burned out of your Mac with an original part for simplicity sake.

Longer answer:
3,1 PSU may not easily fit in a 1,1, but a 1,1 in a 3,1 should fit.
This is due to how the 1,1 originally routes its harness plugs through the bulkhead, since the plugs all connect at the bulk head unless you cut it open further.

1,1 Power supplies have less amps then 3,1 power supplies. So if you use a 1,1 PSU in a 3,1 Pro be careful of how big of video card you run and how many amps your pulling with the bigger wattage CPU's that came as options on the 2008's.

Lastly the 1,1 and 3,1 plugs on the PSU are labeled different. I can't remember which is which, but one has plugs marked in letters (A, B, C, D) while the other has numbers (PS1, PS2, PS3). Plug A to 1, B to 2, etc and it will work fine. The last plug on one if I remember is not labeled/blank, but just plug the blank into whatever you have left. They only fit whats remaining so you can't really mess it up.
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