HD7790 Overheating Problem

[Lucky2307]

Hello,

I've been having some overheating problem with my Sapphire HD7790 Dual X. I don't really know when it started (Don't usually check my temps). I've been searching for solutions but can't seem to find the right one. I've uploaded a screenshot of MSI Afterburner and HWInfo. As you can see, the temperature went up to 99 and throttled.

Here some things I did and things that I checked:

1. I've cleaned the heatsink and changed the thermal paste with Arctic's MX4

2. The fan is running normally

3. I've tried it with open case, still the same result

 

I don't think it's an airflow problem, because my cpu is running normally (around 68 c max with stock cooler).

Since this is an old gpu, there's a slight sag in the pcb. Could it be that VRM isn't getting cooled as it's supposed to?

 

Bonus question: As you can see, the gpu usage in afterburner jumps up and down even when I'm not playing any games. Is that normal? (I did a virus scan with Malwarebytes already)

 

Your help is much appreciated.

 

[Lucky2307]

Update: While the stress test running, I tried putting a stick under the gpu to lift it. Apparently it improved the temperature to stable 90 c.

So my question is

1. What is exactly happening? Is the die not covered fully? Or the vrm not being cooled properly?

2. How do I fix this problem?