MacPro 5,1 mid-2010 dual processor temperature settings?

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Level 1

89 points

MacPro 5,1 mid-2010 dual processor temperature settings?

Hi everyone,

I just recently upgraded my mid-2010 MacPro 5,1 (not 2009 flashed) single processor 4-core 2.8 GHz tray with 32 GB RAM to a dual processor 12-core tray with 64 GB RAM. I removed the original 2.93 GHz processors the dual tray came with and replaced them with 2 X5690 3.46 GHz processors.

To check the temps, I encoded a rather large video file with HandBrake.

During the encoding, I noticed that CPU A ran hotter than CPU B- about 92-98º C for CPU A and about 71-75º C for CPU B.

Is it normal for CPU A to run hotter than CPU B? Idle temps seem about the same, with CPU A running just slightly above CPU B's temps.

Forgive my ignorance, but which one is CPU A on the board (the left or the right one)?

Thanks in advance for the info!

Mac Pro, OS X Yosemite (10.10.5), 3.46 GHz Hexa Core- Intel

Posted on May 26, 2016 5:41 PM

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Answer 1

May 27, 2016 4:29 AM in response to RAfBOy

Yes it is normal for CPU A to be hotter than CPU B. This is because air is sucked in at the front of the Mac Pro and first passes over CPU B (which is nearest the front), it gets warmed by CPU B, and then passes over CPU A and gets warmed even more. Since the air is already warmer when it reaches CPU A it is less able to cool CPU A.

Supposedly the temperature different will be between 5˚c and 9˚c, so your difference seems a bit high.

It would be worth checking the fans and heat sinks are clear of dust, and perhaps consider re-installing CPU A with fresh heat-sink compound between it and the heat-sink.

I did a similar upgrade to my 5,1 and my temp difference was in line with the range above but I have not pushed it as hard as you have.

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Answer 2

RAfBOy Author

Level 1

89 points

May 27, 2016 4:33 AM in response to lllaass

Thank you for both of your responses.

I used Arctic Silver thermal paste after I cleaned both processors and heat sinks with the cleaner, and applied the Arctic Silver purifier.

I think I may have been a bit too liberal in the application. I did the 'X' method, spread it around with a card, and then also did the 'pea' in the center.

Some of the research suggests that too much paste may be just as bad as too little.

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Answer 3

lllaass

Level 10

210,513 points

May 27, 2016 4:29 AM in response to RAfBOy

I would say what you see is normal.

Only a few apps can utilize all cores and the cores in CPU A are preferably used.

What heatsink paste did you use?

For what CPU is A and B see page 22 of:

http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf

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Answer 4

RAfBOy Author

Level 1

89 points

May 28, 2016 1:26 PM in response to lllaass

I figured it would...

So I took off the heatsinks again, and boy(!) am I glad I did!

One of the processors wasn't too bad, though it was still too much thermal paste, but the other! When I pulled off the heat sink, there was thermal paste EVERYWHERE. It even got on the processor holder and spring arm. I spent about 40 minutes thoroughly cleaning everything with the Arctic Silver cleaner, then purified everything thoroughly.

I used the pea method (only) on both processors this time.

The temps for processor A are still a bit high for me; 55º C for A core PCECI and 48º C for the heat sink- from just web surfing and downloading (CPU B PCECI 38º C and heat sink 36º C... ambient is 30º C). But I read that the temps will settle to normal when the processors heat up and the thermal paste spreads more evenly from the heat and use.

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