Does anybody know if it is possible to replace the complete dual CPU processor board (tray) of a MacPro4,1, with a single CPU processor board of the same model? I do not wish to use 2 CPU's anymore and downgrade to a single CPU to have more and cheaper upgrade options. Thanks!
MacBook Pro, Mac OS X (10.6.8), null
I've done a bit more research here and stumbled over the following.
The MacPro4,1 (early 2009) apparently ships with 2 different Backplane boards:
Ver. 1 p/n: 661-4996, EEE codes: 1LT, 7A1
Ver. 2 p/n: 661-5444, EEE codes: CU7, DD4G, A71 BH7
The 8-core Processor board: p/n: 661-4998, EEE codes: 1LU, BXZ, DCVH
The 4-core Processor board: p/n: 661-4999, EEE codes: 4MF, BY0, DCVJ
According to the above, there is no specific Backplane for the 4-core or 8-core Processor board. So the Processor boards are interchangeable.
What I don't know yet is the difference between ver. 1 and ver. 2 Backplane boards:
According to some readings, the best way to find if a part is correct is to match the EEE code. My 8-core Processor board has the following Barcode:
J5906F1UH1LUB, which means according to xxxxxxxEEEx, the EEE code is 1LU. And the link below suggest that 1LT should be the corresponding Backplane board. I obviously have a ver. 1 Backplane board.
Does anyone know the difference between ver. 1 and 2 Backplane boards?
What 4-core Processor board would be a match for Backplane with EEE 1LT?
This looks to be more of duplicate thread and details that belong in your other thread rather than a separate thread.
This one is about 4,1 processor boards in a 4,1 machine with official firmware and about differences between version 1 and version 2 backplane.
The other one is about mixing 5,1 and 4,1 and 5,1 firmware upgrade. I would not combine these threads, otherwise it would be even more confusing.
FWIW, I found the following:
http://www.thebookyard.com/product.php?products_id=6690
http://www.thebookyard.com/product.php?products_id=6691
Version 1 is only suitable for replacing logic boards with an EEE code of 7A1.
Version 2 is suitable for replacing logic boards with an EEE code of CU7 or DD4G but is a replacement for the version 1 backplane board which carries the EEE code 7A1 and so may also be used in place of this original version.
However, so far I have not been able to find out what the difference is and whether it really matters.
You can switch these boards with ease.
Juts stay in same family. Either 4,1 or 5,1 family.
And make sure your seller isn't confused, the boards stay the same even once flashed as 5,1. So a 4,1 board that has been flashed to 5,1 is still a 4,1.
Thanks for the response.
I can confirm that replacing a 8-core with a quad-core processor board worked fine. I did not pay attention to the EEE number, so either I was lucky or it simply does not matter. The SMC version of the system and CPU board is the same 1.39f5.
I'm going to upgrade the firmware to 5,1 next using the special firmware app. Obviously I can only patch a working unit, so if I patch the system and the quad cpu board to 5,1, I would probably run into trouble when plugging the 8-core back in, which is still on 4,1? Will the system see the 8-core board at all? I guess what I will have to do prior to installing the 8-core again is simply to downgrade the system firmware back to 4,1. Luckily, this can be done.
It turns out there is no problem to exchange the quad-core CPU board with the 8-core CPU board even after upgrading from Mac Pro 4,1 to 5,1 using the special firmware upgrade tool. The tool installs a different boot rom, but does not update the SMC version of the CPU board and system, which have to match.
For more detailed info: Installing MacPro5,1 Processor Tray into MacPro4,1
Just to reaffirm that switching the 8-core and quad core processor board is not a problem, even after the 4,1 -> 5,1 upgrade, please see the below screenshots. Other sources on the web may tell you otherwise, but this is not true according to my real tests:
Replacing 2 CPU board with 1 CPU board in MacPro4,1
