GPU Temperature Drops by 30℃ in 1 Second

[primeven]

Hello everyone,

I have an old laptop with GeForce 820M in it. Recently I cleaned the fan and heatsink, applied thermal paste and everything was perfect. When I checked the temperature everything was looking good except for the GPU temp. As you can see below, AIDA64 reads the temperature like that, sometimes it doesn't even read. Other softwares didn't measure the GPU temp. I thought maybe sensor was damaged somehow but I didn't think much of it. Then I started a game, and GPU temp skyrocketed to 90℃ and when I close the game it dropped back to 60℃ in literally 1 second!

Is it possible that the diode is damaged and doesn't measure temperature accurately? Or did I do something wrong while applying thermal paste?

 

[Caring1]

GPU-z doesn't detect the Temperature?

 

[primeven]

GPU-z doesn't detect the Temperature?

Here's the log file generated by GPU-Z. If you look at the temp at 15:41:10, it's 91.0℃ and drops to 73.0℃ after 1 second.

And before reapplying the thermal paste, it never reached above 80℃.

 

[pavle]

Any thermal paste needs to "settle in", that's what I observed when applying it anew. The next day the component you applied it to shows lower temperature (a few degrees).
Odd thing is that with new past your GPU temperature went from 80°C to over 90; either the paste is worse than the one before or also - the heat-sink might not touch the GPU thoroughly.
Also - did you perhaps put too much thermal paste on the GPU?
Oh and that drop from 90+ to 73 is nothing strange - once there isn't any significant current flowing through GPU, temperature drops mightily.

 

[primeven]

Any thermal paste needs to "settle in", that's what I observed when applying it anew. The next day the component you applied it to shows lower temperature (a few degrees).
Odd thing is that with new past your GPU temperature went from 80°C to over 90; either the paste is worse than the one before or also - the heat-sink might not touch the GPU thoroughly.
Also - did you perhaps put too much thermal paste on the GPU?
Oh and that drop from 90+ to 73 is nothing strange - once there isn't any significant current flowing through GPU, temperature drops mightily.

Thank you for your reply. I indeed tightened the screws on heatsink as far as they could go. Should I just disassemble the heatsink and reapply the thermal paste at this point?

 

[pavle]

I mean it's really suspicious that GPU temp would be over 90°C compared to before 80°. When I'm replacing e.g. factory grey paste on GPUs with my sort of generic white paste, temp only goes up a degree or 2 - that's when it settles in.
However I had an odd case with my GTX 470 (Gigabyte SuperOverclock) - I replaced that paste with the white one and the card got quite hot afterwards; since I only had it for some tests I didn't think much of it, it's Fermi after all. However upon taking it to mr. madness777 (also on this Forum), we/he discovered that the heatsink didn't properly touch the GPU, I guess it featured a bend from the factory. Go figure.
At that point I said I never saw anthing like that before in my life.

I'd say check anyway if the heatsink has proper contact with the GPU and that there isn't too much paste because it can act as insulator if too thick.

 

[primeven]

I mean it's really suspicious that GPU temp would be over 90°C compared to before 80°. When I'm replacing e.g. factory grey paste on GPUs with my sort of generic white paste, temp only goes up a degree or 2 - that's when it settles in.
However I had an odd case with my GTX 470 (Gigabyte SuperOverclock) - I replaced that paste with the white one and the card got quite hot afterwards; since I only had it for some tests I didn't think much of it, it's Fermi after all. However upon taking it to mr. madness777 (also on this Forum), we/he discovered that the heatsink didn't properly touch the GPU, I guess it featured a bend from the factory. Go figure.
At that point I said I never saw anthing like that before in my life.

I'd say check anyway if the heatsink has proper contact with the GPU and that there isn't too much paste because it can act as insulator if too thick.

Okay thank you so much. I'm gonna check the heatsink, I hope it's not bend or anything. Should I replace the thermal paste even though it's been a couple days since the last time I changed? Should I just check if heatsink touching properly?

 

[pavle]

I'd say just check there isn't too much paste and that heatsink is covering the whole chip.

 

[primeven]

Hello again, I disassembled everything again, reapplied the thermal paste to my GPU. But nothing changed. I don't understand how CPU temperatures dropped drastically while GPU temperatures increased compared to old paste, knowing that those parts share the same heatsink.

I applied the thermal paste to GPU just like I did on CPU, a thin layer of thermal paste on chips
I tightened the screws all the way down to GPU.

Would it be ideal to run my 820M at 85°C while playing games? Because I think I'll just go with it for now.

 

[Rowsol]

85c is fine and pretty normal for laptops.

 

[pavle]

Agreed; from time to time (depends on dustiness of surroundings) check the intake side of the fan cooling those components (heatsink right after the blower). Shag carpeting like dust mattress is known to form on the intake side preventing airflow with any kind of blower system really. Same goes for blower graphics cards.

 

[agentnathan009]

Hello everyone,

I have an old laptop with GeForce 820M in it. Recently I cleaned the fan and heatsink, applied thermal paste and everything was perfect. When I checked the temperature everything was looking good except for the GPU temp. As you can see below, AIDA64 reads the temperature like that, sometimes it doesn't even read. Other softwares didn't measure the GPU temp. I thought maybe sensor was damaged somehow but I didn't think much of it. Then I started a game, and GPU temp skyrocketed to 90℃ and when I close the game it dropped back to 60℃ in literally 1 second!

Is it possible that the diode is damaged and doesn't measure temperature accurately? Or did I do something wrong while applying thermal paste?



View attachment 181290

So, processors and GPUs don't retain heat very well, though they can produce plenty of heat for their size. Like a light bulb filament, once you cut power, the heat drops quickly with the filament going from glowing hot to not glowing in a matter of seconds. A heatsink is designed to dissipate heat from a heat source, such as you CPU or GPU. Since the heatsink warms slowly as it get heat loaded and cools slowly as heat dissipates, the reasonable conclusion to your issue is that you have a contact issue where heatsink is not properly contacting chip, or the thermal paste has dried out and is not transferring heat to heatsink.

 

[cst1992]

heatsink is not properly contacting chip, or the thermal paste has dried out and is not transferring heat to heatsink.

Air bubbles/gaps in the thermal paste and excess thermal paste also cause these issues.

 

[Mussels]

Did the laptop use thermal paste or thermal PAD originally? you may need something thicker to contact the heatsink, if it used a pad originally.

and an obvious thing, is the fan(s) spinning correctly?