cMP 5.1 dual CPU.
The machine was running well, no big issues. At least I thought. Haven't measured temperature before. Then I wanted to make it silent and replaced the fans. I had to do it 2-3 times, coz of the wrong fans... At least I think that's where the problems occurred.
The Northbridge temperature is now going so high, that the machine just doesn't react anymore after a couple of minutes.
I replaced the northernbridge bolts by 3M steel bolts like here:
www.ifixit.com
I put a new thermal paste on the Northbridge: Arctic Silver 5 9 W/m K, 3.50 g. But it didn't help. Still too hot.
Another thing: Here I read that the Northbridge Watt value should be 20W:
discussions.apple.com
Mine shows only 13W. Maybe this is also contributing somehow to the problem?
In the same thread they say, maybe even a bad RAM can be a problem. The RAM in this machine is sometimes showing entirely, sometimes only 3 of 4. But I can't imagine that this can have anything to do with the Northern Bridge..
____
My thoughts:
Please help. Thanks!
DISCLAIMER:
Didn't know at that time that there is an elegant way to replace fans, like this:
https://forums.macrumors.com/thread...rket-fans-with-automatic-smc-control.2232167/
I've followed a youtube tutorial where one replaces all fans by Noctua PWM fans and control them via a separate small control "Quadro" unit via USB. By replacing the fans I think I had to disconnect the native temp sensor cable on cpu heatsink. Just saying this, if you see some strange temperature of the cpu sink, which I think is not relevant to this whole topic, but maybe I'm wrong.
The machine was running well, no big issues. At least I thought. Haven't measured temperature before. Then I wanted to make it silent and replaced the fans. I had to do it 2-3 times, coz of the wrong fans... At least I think that's where the problems occurred.
The Northbridge temperature is now going so high, that the machine just doesn't react anymore after a couple of minutes.
I replaced the northernbridge bolts by 3M steel bolts like here:
Mac Pro Single CPU Northbridge Heatsink Repair
Step by Step Illustrated Guide These are easy to follow instructions for replacing the plastic stays on the northbridge heatsink in a Mac Pro 4,1 &...
www.ifixit.com
I put a new thermal paste on the Northbridge: Arctic Silver 5 9 W/m K, 3.50 g. But it didn't help. Still too hot.
Another thing: Here I read that the Northbridge Watt value should be 20W:
Normal Northbridge temp? - Apple Community
In the same thread they say, maybe even a bad RAM can be a problem. The RAM in this machine is sometimes showing entirely, sometimes only 3 of 4. But I can't imagine that this can have anything to do with the Northern Bridge..
____
My thoughts:
- Maybe the Heatsink is bent due to the high temperatures and just can't seat entirely any more on the Northbridge, so it can't receive the heat and do the cooling job? Don't know if I've tightened it too much or not enough. I tried 3 different pressures, but no impact on the temperature. The last, most tight is on the picture.
- I have another cMP5.1 here, so I could maybe use some parts from there for the diagnostic purpose. Should I try to replace the Northbridge with the one from another machine?
- Do you see anything strange on the HWMonitor statistics?
- What do you think about the 20W and RAM?
- What would you do first?
Please help. Thanks!
DISCLAIMER:
Didn't know at that time that there is an elegant way to replace fans, like this:
https://forums.macrumors.com/thread...rket-fans-with-automatic-smc-control.2232167/
I've followed a youtube tutorial where one replaces all fans by Noctua PWM fans and control them via a separate small control "Quadro" unit via USB. By replacing the fans I think I had to disconnect the native temp sensor cable on cpu heatsink. Just saying this, if you see some strange temperature of the cpu sink, which I think is not relevant to this whole topic, but maybe I'm wrong.