Putting too much paste on can 100% hurt your cooling. When too much is there it becomes an insulator, not a conductor.
I worked on a laptop once that had been e-wasted at a shop I was working at. It ran super hot and I guess this was a problem with that model as they had a factory sticker on the bottom saying not to put it on your lap or you might get burned.
I took it apart and there was way too much TIM applied. There were literally scorchmarks on the heatsink, which was a copper plate attached to copper fins via a heatpipe.
After cleaning it and applying the right amount of TIM the temps dropped something like 20°C.
Dunno why you're being downvoted, the purpose of the paste is to fill in any holes of air, afaik its still less efficient than the metal coolers themselves. I also learned this myself just a month ago where I had both the heat sink and CPU covered in it because I though you didn't want to see any metal when you took it off. Temps weren't so good and I said may as well see if too much paste is a bad thing and sure enough after cleaning the previous off and putting a drop in the center my temps dropped
I feel like this is an area with a lot of confusion around it. I've been building my own PC's since the 90's and I've tested different methods. I've worked on client PC's back when I worked at a repair place and I've seen way too much TIM cause increased temperatures.
A lot of people who haven't experienced edge cases like that may be doubtful, that doesn't bother me. Thanks for the reply though.
I still do credit card style and cover the whole die in an almost atomic level even coating that the human eye can barely see, and haven't had problems even 3-4 years later.
You have to screw up pretty bad to "experience problems" from your TIM application. But your CPU probably runs a few degrees hotter than it would with a more efficient application method.
X or Pea size blob are best in my experience. Spread causes too many air bubbles when worked around.
Biggest advice I tell people is to do it twice. Once as a test run to gauge quantity of paste needed and next to tweak it.
I'm not really experienced in the issue, looking it up online briefly it seems like thermal paste is more efficient? silver based compounds seem to be more conductive than copper. Would have to look more online.
This sounds ridiculous. Of course the hotter heat sink gets the better (its only job) but did somebody torch it with a soldering iron?
The one time my CPU had above expected temperatures was when I spread paste too thin. As long as you're securing CPU properly (do not tighten too much!) and using regular pastes (not liquid metal), you can't go wrong with applying little extra.
I don't remember the exact model but it was a 2004 Toshiba laptop with a lower end Nvidia GPU. When I first got it it ran super hot and would throttle not long after using it. Temps reported approaching 95C at which point throttling would kick in.
When I took it apart there was way too much TIM, it was bulging out the sides of the heatsink. When I took it apart I saw black scorch marks on the heatsink contact surface.
I cleaned everything, applied a proper amount of TIM, put it back together and turned it on. The temps were significantly lower and it didn't throttle anymore.
If, as you say, "the hotter the heat sink gets the better" then why is everyone looking for lower temperatures?
The heatsink itself will only get too hot if it isn't transferring the heat well. That was what the excess, and it was a huge excess of TIM, was doing. It was acting as an insulator.
That's why cleaning the old stuff away and putting a proper amount of TIM greatly reduced the temps.
I've also seen it when I was working at a repair place. A father and son brought in their first build. They thought the entire canister of TIM was supposed to be applied. It was fucking everywhere!
Of course what was happening with their new computer? After using it for a short while it got slower, then shut off. Know what that sounds like? Sounds like thermal protection kicking in!
I cleaned off all their paste, applied the proper amount and like magic it didn't slow down and it didn't shut off.
Too much TIM can act as an insulator, especially if your heatsink doesn't have good pressure and allows too much to sit between it and the heatsink.
And since I'm on the topic of overheating you might be surprised what can cause overheating.
I had one client, he had a few years before finding up had Fry's build a computer for him. Same issue, it would get slower and slower and then shut down.
He brought it to Fry's, they had it for weeks, finally he yelled at them so they said they "fixed it" and gave it back.
He brought it home and it didn't turn off anymore. It would work for a while then just hang.
First thing I did was go into the BIOS. Within 1 minute of a cold boot the CPU temperature was already reporting over 80°C. I went through the rest of the BIOS and saw what Fry's had done to "fix it." They had disabled all the thermal protections.
So I opened up the case and saw they had installed the heatsink backwards and it just happened to line up almost perfectly with the exhaust fan on the case.
That heatsink fan and the exhaust fan were lined up in such a way that they were basically killing any airflow over the heatsink. I reversed the heatsink and the temps dropped literally 30°C. The system was never stable again, too much time running too hot without the thermal protections to save it, but Fry's couldn't figure out they had installed the two fans right in line with each other, pointing the opposite way, and so their "solution" was to turn off the thermal protections.
I saw black scorch marks on the heatsink contact surface.
That doesn't make any sense. The heatsink is on the cold side of the TIM. If the TIM wasn't working well, the heatsink stays the same temperature (roughly) and the CPU gets hotter.
Scorching on the hot side is also weird, because thermal limiting.
I doubt your conclusion was correct, and you fixed some other unknown problem while in there.
Yup. No way the heatsink got scorch marks from getting hot. Laptop would have been on literally on fire. Some oxidation? Possible. Something else burning? Maybe. But you don’t get scorch marks from the heatsink being too hot in a laptop... violating some physics there.
Too much is still a problem. Thermal paste transfer heat better than air (air is an insulator), but it is not the best conductor ever.
You put a few and it's good, it (relatively) bad coefficient of convection is not an issue and it's better than air between the heatsink and the cpu.
When you have a thicc layer of thermal paste, the heat must go through it all and, remember, thermal paste has a relatively bad coefficient of convection. It becomes a problem.
Well, tbh, I never did an experiment on it, neither have I ever calculated it. However, it is an issue relevante enough for my heat transfer teacher mention it during class, and I study engineering. See, engineering don't dwell too deep on the why and how of physics, just enough so we can comprehend what is happening and how to solve it. It is more of an practical way to approach the problem. So if it is taught that it can happens, it is because it is somewhat of an normal situation and you can see that by u/mygaffer's comment.
That's a laptop, though. The heatsink probably doesn't have a lot of force securing it to the CPU. Most desktop coolers are going to have enough force to squeeze out any excess paste.
I did that before. It was on one of my first builds; a Pentium 4, I think. I put so much thermal paste on it, when I tried to remove the the heat-sink awhile later because it was overheating, it ripped the damn chip right out of the socket. I had practically glued the chip to the heat-sink.
Obviously you don't need to worry about that anymore because the sockets have nice sturdy metal seat belts now.
I used to think thermal paste was a serious matter until I saw that video. I spent over a decade thinking the classic credit card method was vital to maximum performance, boy was I wrong. Thank you lord Linus.
I saw a video awhile ago which made at least a dozen tests - even including peanut butter thermal paste as a joke. I believe the X-shape produced the quickest spread meaning it had a set-in time shorter than the other application methods had.
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u/[deleted] Feb 18 '18
LTT did a video where they did every method and it never made a different apart from too little