[SOLVED] Northbridge overheat or power supply problem? Which thermal paste to use on overheated Northbridge of a Gigabyte GA-990FXA-UD3 motherboard?

May 10, 2021
I have a Gigabyte GA-990FXA-UD3 v1.2 motherboard with AMD with 4 x 4 Gb DDR3 RAM.

Under higher performance (CPU or memory intensive operations, or long disk copy operations)
the Northbridge of this board is overheated reaches 80 °C, then the motherboard starts beeping.

Happened error events:
  • Random BSOD sometimes.
  • It happened to get long beeps at boot, when using Gigabyte GT-9600 videocard, while using a low performance card, booted without error.
  • It happened to get long beeps at boot, when using 4 x 4 Gb DDR3 RAM, while using 2 x 4 or 3 x 4 Gb DDR3 RAM, booted without error. There was no problems with these 4 x 4 Gb DDR3 RAM modules, which was used since a few years. I replaced the modules randomly to boot well with 3 x 4 RAM modules. Also made memory tests with 3 x 4 RAM modules. So I made sure, the memory modules are good.

Now, after a week the computer boots well, with same videocard, same 4x4 RAM modules, same power supply.

Based of these symptoms I predicted, power supply problem or Northbridge overheat problem.

I tested with another power supply, the configuration worked well.
So I ordered a new power supply.

Before I test the new power supply, I wanted to test again the motherboard, to reproduce the errors again, before using the new power supply.
Strange, that the board booted well, I was able to insert the GT-9600 videocard, the 4x4 Gb RAM, the boot successfully.
RAM tests went well, booted into Hiren's Boot CD, tested memory in Windows mini XP, and some stress tests, all successfully.
Then attached the 2 x Areca ARC-1210 RAID card, attached 2 x SSD + 2 x HDD (both with RAID1 volumes).
Booted well into Windows 7 Pro.

I used then OCCT stress test tool (https://www.ocbase.com/), which showed 80 °C at Northbridge, and the started beeping at this time.

I don't know how I got videocard & RAM error beeps at boot, then after a week it boots well, while nothing is changed.

Anyway, the Northbridge overheating is still problem.
I have to change the Northbridge thermal paste for sure.
I will likely keep the power supply in case the old power supply still dies.

My questions:
1) May Northbridge overheating be responsible for all such strange symptoms and errors?

2) Could you skip the power supply as problem source, or should I still count with this possibility?

3) Which thermal paste to use? Arctic Silver 5 Thermal Grease? Is it safe to use?
I did read, that AS5 (Arctic Silver 5 Thermal Grease) is good for Northbridge, because it is not electrically conductive.
Is it safe to use?

4) Or do you recommend something other?

5) Should I replace thermal grease on all heatsinks, including Northbridge, Southbridge, MOS heatsink (above CPU)?

6) Should I use Arctic Silver 5 Thermal Grease on all of them?



AS5 is an older compound, but it still works. As you mentioned it no longer contains silver as it once did.

Really any thermal compound would work, and that might not be the only problem. Could just be a failing chip that is consuming more power as it ages.

As for the other heatsinks, you don't typically find thermal compound, but rather thermal pads, in use. You could get new pads, but it is best to measure and see what thickness they are.

Complete disassembly can often take care of little connection problems that happen over time. You leave a graphics card in a slot for a few years and it will sag down, repeated temperature cycles will slowly make it move back and forth. Dust intrusion into the slots.
May 10, 2021
Finally I ordered an Arctic Silver 5 Thermal Grease (AS5) and replaced the thermal paste under the Northbridge and the CPU.
I used 1 point type placement of thermal paste on Northbridge and 2 parallel lines + 1 point of thermal paste on CPU cooler (because it has 2 copper heatpipes).

Unfortunately the Northbridge still reaches 80 °C in 7 minutes when using AIDA64 stress test named "Stress FPU".
I used OCCT as monitoring software.

Strange, that CPU temperature shows constantly 12 °C, which must be wrong.
BIOS shows CPU temperature.

Attaching OCCT screenshot.

I'm disappointed, that thermal paste change on Northbridge did not help :-(((

Any ideas are welcome how to fix the overheating situation.