Good idea ActionableMango, I went ahead to contribute and made a list of what I know is compatible:
Hmmm, great job! You beat me to it, AND yours looks much better than mine. I do have more information in mine though. We should join forces and start a new thread with a proper title so people can find it. I think it will be useful to many. Do you want to or shall I?
Here is what I have:
Mac Pro CPU Compatibility Guide
Warnings:
- Any and all information here may be incorrect. Use at your own risk.
Notes:
- I have included memory information because in some cases the memory's speed or maximum capacity is affected by the CPU choice.
- I realize there are some slower CPUs that probably work but are not listed. I purposely left out anything that was slower than the base model CPU offered by Apple in order to keep the list more concise.
Key:
* An asterisk denotes that I have found some sort of confirmation that this CPU worked. This includes anything offered by Apple (BTO/CTO), third party upgrade guides or commercial services (such as Barefeats, OWC, or xlr8yourmac), or simply individuals claiming personal success in a forum somewhere.
? A question mark denotes a processor that almost certainly works in a Mac Pro, and for which I found at least one person who recommends it. However, I have been unable to find a post which verifies that it actually does work in a Mac Pro.
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Mac Pro 6,1
Model Cores Clock
E5-2697 v2* 12 2.70 GHz
E5-2690 v2* 10 3.00 GHz
E5-2667 v2* 8 3.30 GHz
E5-1680 v2* 8 3.00 GHz
E5-1660 v2* 6 3.70 GHz
E5-1650 v2* 6 3.50 GHz
E5-1620 v2* 4 3.70 GHz
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Mac Pro 5,1 and 4,1
- To use 6-core models and run RAM at 1333, the 4,1 will need the firmware upgrade to 5,1, found here: http://forum.netkas.org/index.php/topic,852.0.html
- One dual-processor-model CPU works fine in a single-processor Mac Pro, and increases its maximum RAM from 56 to 64GB.
- One single-processor-model CPU technically works in a dual-processor Mac Pro, but this causes an error state with the CPU fan going full blast.
- 4,1 dual-processor Mac Pros use special, "lidless" CPUs. You either need to buy lidless CPUs, de-lid them yourself, or pay for de-lidding service, so that the CPUs are the proper height. Failure to do this results in very expensive damage when the heatsink is tightened down. Some people have kept the lids on, but were extremely careful about not tightening down the heat sink too much. Other people have kept the lids on, but added washer stacks (of equivalent height to the lid difference) to where the tightening screws go--this is intended to prevent the heat sink from overtightening and causing damage.
- No, the X5687 (3.6GHz quad-core) and the X5698 (4.4GHz dual-core) do not work in Mac Pros. I don't want to list every CPU that doesn't work with a Mac, but these two are asked about often enough to note here.
Dual-Processor Xeon Models:
- 128GB maximum RAM for dual-processor Mac Pros
- 64GB maximum RAM for single-processor Mac Pros using one of these dual-processor-capable CPUs
Model Cores Clock MemClock Max Memory
X5690* 6x2 3.46 GHz 1333 64/128GB (single/dual processor MP)
X5680* 6x2 3.33 GHz 1333 64/128GB (single/dual processor MP)
X5679* 6x2 3.20 GHz 1333 64/128GB (single/dual processor MP)
X5675* 6x2 3.06 GHz 1333 64/128GB (single/dual processor MP)
X5670* 6x2 2.93 GHz 1333 64/128GB (single/dual processor MP)
X5660* 6x2 2.80 GHz 1333 64/128GB (single/dual processor MP)
X5650* 6x2 2.66 GHz 1333 64/128GB (single/dual processor MP)
X5677* 4x2 3.46 GHz 1333 64/128GB (single/dual processor MP)
E5570* 4x2 2.93 GHz 1066 64/128GB (single/dual processor MP)
E5550* 4x2 2.66 GHz 1066 64/128GB (single/dual processor MP)
E5520* 4x2 2.26 GHz 1066 64/128GB (single/dual processor MP)
Single-Processor Xeon Models:
- 56GB maximum RAM (3x16GB + 1x8GB)
Model Cores Clock MemClock
W3690* 6 3.46 GHz 1333
W3680* 6 3.33 GHz 1333
W3670* 6 3.20 GHz 1066
W3580* 4 3.33 GHz 1333
W3570* 4 3.20 GHz 1333
W3565* 4 3.20 GHz 1066
W3550? 4 3.06 GHz 1066
W3540* 4 2.93 GHz 1066
W3530* 4 2.80 GHz 1066
W3520* 4 2.66 GHz 1066
Single-Processor i7 Models:
- All Mac Pros come with Xeons. The i7 equivalents are listed here because some of them have been verified compatible with Mac Pros and ECC memory, although the ECC function will not work. Xeons are recommended, but the i7 is a valid upgrade choice and multiple people here on MR have done so.
- The 56GB maximum RAM for single-processor machines was tested on Xeons. The i7 CPUs probably have the same limit.
Model Cores Clock MemClock
i7-990X* 6 3.46 GHz 1333
i7-980X* 6 3.33 GHz 1333
i7-980 ? 6 3.33 GHz 1066
i7-970 * 6 3.20 GHz 1066
i7-975 * 4 3.33 GHz 1333
i7-965 * 4 3.20 GHz 1333
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Mac Pro 3,1
- 64GB maximum RAM
- Single-processor Mac Pro 3,1 has 4 cores only, not the 4x2 listed below
Model Cores Clock
E5462* 4x2 2.8 GHz
E5472* 4x2 3.0 GHz
X5482* 4x2 3.2 GHz
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Mac Pro 2,1 and 1,1
- 32GB maximum RAM for 1,1 (increases to 64GB if flashed with 2,1 firmware)
- 64GB maximum RAM for 2,1
- To use 4-core CPUs, the 1,1 will need a firmware flashed to 2,1.
- The 1,1 to 2,1 firmware flash requires Snow Leopard (or newer) to run. It can be found here: http://forum.netkas.org/index.php/topic,1094.0.html
Model Cores Clock
X5365* 4x2 3.00
X5355* 4x2 2.66
E5345* 4x2 2.33
5160* 2x2 3.00
5150* 2x2 2.66
5130* 2x2 2.00
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How you can help:
- If you have personal knowledge on the topic, please review the content for errors or omissions.
- Constructive criticism is welcome.
- Help verify CPUs that are listed as unverified (marked "?"). If you've seen someone else claim a processor works, link to that post. If you've personally tested a processor that's unverified on the list, please respond to verify.
[doublepost=1454710698][/doublepost]The formatting in mine is weird. When I click "edit", the columns all line up, but when not in "edit" mode, the tabs are lost and all the columns are jammed together.