MP 1,1-5,1 Arctic thermal paste Mac Pro 5.1 CPU replacement

Fcis

macrumors member
Original poster
Jun 23, 2020
59
2
I am planning to replace my CPU on my Mac Pro 5,1 and I wonder how much Arctic thermal paste ARCTIC MX-4 2g I should place on my new CPU? I saw some people on videos placing a dot in the centre or a line from side to side,....Any advice what is the best way? And I also wonder when screwing off the towers do I need to count the cycles of each screw and do the same when screwing them back on? since I read that with the Mac Pro 5,1 when you unscrew them the tower will kind of pop up and when you screw them back you will notice once it stop, so you don't need to count turns. Any advice?
 

h9826790

macrumors G5
Apr 3, 2014
14,107
6,732
Hong Kong
Any amount, any method, as long as it can cover the whole IHS.

Theoretically, as thin as possible. Reality, doesn't really matter, may be just 1-2°C difference at the end.

As general rule, more is better than less (if you don't know what is the correct amount).

Anyway, this is the instruction from Apple manual for 5,1. Best amount, 0.2cc. Best method, a stop sign.
Screenshot 2020-06-30 at 2.26.04 AM.png
 
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DPUser

macrumors 6502a
Jan 17, 2012
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Rancho Bohemia, California
How much Arctic thermal paste ARCTIC MX-4 2g I should place on my new CPU?
There is a guide put out by the Arctic Silver people; they recommend single line down the middle (check the guide for orientation) for the Mac Pro's Xeon CPUs.

When screwing off the towers do I need to count the cycles of each screw and do the same when screwing them back on? since I read that with the Mac Pro 5,1 when you unscrew them the tower will kind of pop up and when you screw them back you will notice once it stop, so you don't need to count turns.
As long as it is a true 5,1 (not a 4,1>5,1 update), yes. Tighten all the way. No need to count turns.
 

Fcis

macrumors member
Original poster
Jun 23, 2020
59
2
Any amount, any method, as long as it can cover the whole IHS.

Theoretically, as thin as possible. Reality, doesn't really matter, may be just 1-2°C difference at the end.

As general rule, more is better than less (if you don't know what is the correct amount).

Anyway, this is the instruction from Apple manual for 5,1. Best amount, 0.2cc. Best method, a stop sign.
View attachment 929118

I've just installed the new CPUs and ran Geekbennch and here are the results https://browser.geekbench.com/v5/cpu/2739066 Could you have a look? and while it was running intensively I can see right light blinking as shown in the below photo, is that normal or it indicates a problem? The red light normally doesn't flash when running the machine normally. I mean how to know that I've done the right thing and applied correct amount of thermal paste for example?

And this is Macs Fan Control:

Screen Shot 2020-06-29 at 23.11.52.png


Photo 29-6-20, 10 39 10 pm.jpg

- - Post merged: - -

There is a guide put out by the Arctic Silver people; they recommend single line down the middle (check the guide for orientation) for the Mac Pro's Xeon CPUs.



As long as it is a true 5,1 (not a 4,1>5,1 update), yes. Tighten all the way. No need to count turns.

Can you check my previous message and advise? :)
 
Last edited:

KeesMacPro

macrumors regular
Nov 7, 2019
211
40
Looks like CPU B heatsink is not properly seated / not enough thermal paste/ screws not tight enough.
I'd redo CPU B , and before you start turning the screws, check that the heatsink is positioned straight , without pushing and start turning the screws crosswise, one after another , each e.g. 1 turn, check alignment , until you feel they're all equally tight. If you would number them from 1 to 4, then turn them each 1 turn like number 1-3-2-4. This way the heatsink will stay aligned.
CPU B is the one in front ,left side.

I wouldn't recommend a Benchmark immediately after a CPU upgrade/repaste.
 

Fcis

macrumors member
Original poster
Jun 23, 2020
59
2
Looks like CPU B heatsink is not properly seated / not enough thermal paste/ screws not tight enough.
I'd redo CPU B , and before you start turning the screws, check that the heatsink is positioned straight , without pushing and start turning the screws crosswise, one after another , each e.g. 1 turn, check alignment , until you feel they're all equally tight. If you would number them from 1 to 4, then turn them each 1 turn like number 1-3-2-4. This way the heatsink will stay aligned.
CPU B is the one in front ,left side.
So when you say “redo” you mean cleaning the thermal paste, applying new one and so on?
 

KeesMacPro

macrumors regular
Nov 7, 2019
211
40
So when you say “redo” you mean cleaning the thermal paste, applying new one and so on?
Yes.
The heatsink B is much colder than the CPU.

EDIT: after the repast, I would first check the Temps and check if there's some red light or other odd behavior before feeding it heavy loads.
 
Last edited:

Fcis

macrumors member
Original poster
Jun 23, 2020
59
2
Yes.
The heatsink B is much colder than the CPU.

EDIT: after the repast, I would first check the Temps and check if there's some red light or other odd behavior before feeding it heavy loads.

I've checked and I found that I didn't tighten the heatsink enough until the end so I tightened them without opening them. Now on Macs Fan Control this is the result. What do you think? Or shall I open the heatsinks and do the process all over again?

Screenshot 2020-06-30 at 00.07.11.png
 
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Fcis

macrumors member
Original poster
Jun 23, 2020
59
2
Much better now
I see that now CPU A is the higher one and B is lower, is that normal? and what in terms of the temperature of both is this is a normal temperature? and shall I run any tests? Thanks for your help.
 

h9826790

macrumors G5
Apr 3, 2014
14,107
6,732
Hong Kong
I see that now CPU A is the higher one and B is lower, is that normal? and what in terms of the temperature of both is this is a normal temperature? and shall I run any tests? Thanks for your help.
Normal, you can run Prime95 to stress test the CPU. Anything not above 90°C is considered normal (when under max stress), usually CPU A will stay at around 85°C.
 

Fcis

macrumors member
Original poster
Jun 23, 2020
59
2
Normal, you can run Prime95 to stress test the CPU. Anything not above 90°C is considered normal (when under max stress), usually CPU A will stay at around 85°C.
Thank you. I've downloaded Prime95 and run the Benchmark test and below are the results, but I don't know how to get the CPU temperature report? Is it the "Torture Test"?


Screenshot 2020-06-30 at 00.37.04.png



I run the online test while opening the macsfancontrol and here is the result. I stopped the Prime95 application as it is seems it will take a long time to finish.

Screenshot 2020-06-30 at 00.44.57.png



I also ran Geek Benchmark again and here are the results https://browser.geekbench.com/v5/cpu/2740306
 
Last edited:

h9826790

macrumors G5
Apr 3, 2014
14,107
6,732
Hong Kong
Thank you. I've downloaded Prime95 and run the Benchmark test and below are the results, but I don't know how to get the CPU temperature report? Is it the "Torture Test"?


View attachment 929195


I run the online test while opening the macsfancontrol and here is the result. I stopped the Prime95 application as it is seems it will take a long time to finish.

View attachment 929200


I also ran Geek Benchmark again and here are the results https://browser.geekbench.com/v5/cpu/2740306
As expected, CPU A stay at about 85C. With such low fan speed, your thermal paste application is good.
 
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