Mac Pro 4,1 vs 5,1 heatsinks... are they Interchangeable?

[Yamahawk]

I have a Mac Pro 5,1 and have a dual CPU tray from a 4,1 which is for parts. My question is, are the dual CPU heatsinks interchangeable between the 2009 4,1 dual CPU tray and the 5,1 dual CPU tray? I can purchase a bare 2010 5,1 tray pretty cheap, and if the heatsinks from the 4,1 dual CPU tray are able to bolt on the 5,1 and be used with the lidded CPU's that would be economical for me. Anyone know if there is a way to use the 4,1 heatsinks on the 5,1 tray? Thanks!
Charlie

 

[jimj740]

The heat sinks have a different part number for the 4,1 and 5,1, so they are different. I have no idea if they could be made to work or not... most likely the difference is to account for the higher chip height in the 5,1 since the CPUs retain the heat spreader/lid.

 

[Bubalight]

They are different. In order to make it work you would have to remove the cpu latch brackets and use delidded CPUs just like the 4,1 tray since that is what the 4,1 heat sinks are designed to fit.
Otherwise you would have to mill about 1.8 mil off the die contact area, and doing that would break the heat pipes most likely, so don't even think about it.
If you tried to use it anyway it would crush the cpu into the socket breaking pins, probably break the cpu and the thermal pad on the side of the heatsink wouldn't reach the power transistors so they would overheat and fry.

 

[Yamahawk]

Ok! I appreciate the replies, and thanks for your expertise. Looks like a 4,1 board flashed to 5,1 might be the way to go. I am looking at installing two X5675 Xeon processors, and i have a small vise to delidd them if necessary, and then install in my 5,1 2010 Mac Pro. I have heard about the fan issue, but I believe it is remedied by a SMC and/or PRAM reset, or Macs Fan control. SMC Fan Control should work also. I hope that the board I am receiving may just need cleaning up, as it has corrosion, and bent fins and tray base on it. But the heatsink can be straightened, and the CPU's and heatsinks can be installed on the new ram board. At the least, I paid $100 shipped, so not a great outlay for a dual CPU board.
Charlie

 

[Bubalight]

It won't work the fans will run crazy and there is nothing you can do about it short of sticking pencils in the fans. Which will then cause overheating.

 

[h9826790]

Ok! I appreciate the replies, and thanks for your expertise. Looks like a 4,1 board flashed to 5,1 might be the way to go. I am looking at installing two X5675 Xeon processors, and i have a small vise to delidd them if necessary, and then install in my 5,1 2010 Mac Pro. I have heard about the fan issue, but I believe it is remedied by a SMC and/or PRAM reset, or Macs Fan control. SMC Fan Control should work also. I hope that the board I am receiving may just need cleaning up, as it has corrosion, and bent fins and tray base on it. But the heatsink can be straightened, and the CPU's and heatsinks can be installed on the new ram board. At the least, I paid $100 shipped, so not a great outlay for a dual CPU board.
Charlie

MacsFanControl won't work, there is no SMC for it to work with.

The full fan speed is causing my mismatched SMC firmware, absolutely no fan control software can do anything about that.