[SOLVED] CPU very hot after reapplying thermal paste and I have no idea why

[QuintusSert]

I just reapplied thermal paste and my CPU is idling on 80+ degrees (it kept getting hotter). The fan is spinning. I cleaned both the sink and CPU properly with arcticlean thermal remover and purifier and coffee filters and put a good amount of new MX-4 on top. I just don't understand what went wrong.

 

[siaan312]

I just reapplied thermal paste and my CPU is idling on 80+ degrees (it kept getting hotter). The fan is spinning. I cleaned both the sink and CPU properly with arcticlean thermal remover and purifier and coffee filters and put a good amount of new MX-4 on top. I just don't understand what went wrong.

Is this higher than it was before..?

If yes, then it's probably a bad mount.

 

[Paperdoc]

You say you "put a good amount of new MX-4 on top." By "good amount", do you means lots of it, or did you follow closely the instructions for your CPU chip? Each chip type requires "just the right amount", and you need that much. Too much it NOT good - it makes a thermal paste layer that is too thick and REDUCES heat removal. Review the instructions for that paste and find the RIGHT amount for the particular CPU chip you have.

 

[QuintusSert]

You say you "put a good amount of new MX-4 on top." By "good amount", do you means lots of it, or did you follow closely the instructions for your CPU chip? Each chip type requires "just the right amount", and you need that much. Too much it NOT good - it makes a thermal paste layer that is too thick and REDUCES heat removal. Review the instructions for that paste and find the RIGHT amount for the particular CPU chip you have.

It didn't really have any instructions. I just put about a grain of rice.

 

[rubix_1011]

The "grain of rice" amount might actually be too little for some installations. I would say "size of a half-lentil", but most people don't know what a lentil is.

I

 

[geofelt]

What cpu and cooler are we talking about?
No doubt, 80c. at idle Is way out of line.
Too much paste is not good, I think a grain of rice is about right.
It is hard to use too little.
Most likely, the cooler did not go on level.
Knowing the cooler make/model, I might be able to make a better guess.

 

[hotaru.hino]

The first thing I normally do when I see this is press on the cooler firmly. If the temperature drops, then I know I just have to tighten the screws more or, Intel designed push-pin coolers, find the pin that wasn't actually in. This is assuming of course I tightened the mounting hardware pretty good to begin with. But otherwise, I suspect a botched mounting job.

Note that while too much paste isn't ideal, it also won't lead to excessive temperatures when idling. The amount you reported you put down is fine.

EDIT: I'm also thinking thermal paste placement depends on the CPU. For Zen 2 and Threadripper, the ol' "rice sized blob in the middle" isn't actually ideal. Zen 2 processors have up to three separate dies. Threadripper can have up to 4 dies that need cooling. Having a blob in the middle and getting a nice circle out of it means it's potentially not completely covering every die.

If you really want to make sure you got your bases covered, apply a little paste and use a credit card or something to completely cover it on the heatspreader.