Question Question on remounting a heat sink

[topgun505]

Been a long time since building a system. I installed the CPU and put on the thermal paste (probably put on more than was needed but that's ok). Then put on the Noctua heat sink fins. I was having a bastard of a time getting both screws to catch to get it screwed down into place. One caught right away but the other was not. I lifted up that end of the heat sink a little in order to visualize the alignment and put it back down and finally was able to get the screw to catch. The question is ... since I lifted one side up a few mm , does that open up the possibility that I trapped any tiny air bubbles between the heat sink and the cpu? If so, the best course of action would be to unmount it, clean up all the thermal paste and reapply and redo it? Or should be ok?

 

[COLGeek]

When you tightened both sides all the way, you should have squeezed out any bubbles. I suspect you are fine.

 

[ex_bubblehead]

Absolutely you may very well have trapped air in there by doing what you did. The best course of action is to reapply if there is any question at all.

 

[Paperdoc]

OP, you say, "probably put on more than was needed but that's ok".

NOT! Too much thermal paste is just as bad as too little. A thick layer of paste slows heat flow. You need only the right amount for a thin film sufficient to fill tiny void gaps and not more. Follow the directions for YOUR particular CPU chip according to the maker of the paste. If you think you really do have too much, re-do.

 

[COLGeek]

Noctuas really form a very tight seal if tightened properly. If the TIM was still liquid, the chance of air bubbles is slim.

Too much, as noted, makes a mess and certainly doesn't help with cooling. The tight fit should just lead to the mess part.

 

[RAIDGoblin]

just try it, if your thermals are bad clean it up and try again

 

[geofelt]

You are probably ok as is.
But some considerations:
1. Paste is intended to fill in microscopic pits in the mating surfaces. Paste is a better heat conductor than air, but not as good as metal to metal contact. Too much paste becomes inefficient and possibly a problem if it overflows.

2. To get a screw to catch, turn it first turn the screw counter clockwise until you feel a catch. Then torn to the right.
To get a cooler level turn each screw just a bit at a time.