Poilishing CPU & heat sink a bad idea?

[Rocketdog2112]

Just throwing this out there as an observation...  On one of my older rigs (a Dell XPS 720) running a Intel Core Extreme Q8650, I decided to polish the top of the CPU and the heat sink to a shine thinking it would help with heat transfer. I think I have discovered this to be a mistake in doing so. A couple of days later I removed the heat sink due to higher than normal CPU temps and noticed that the thermal paste was barely evident on the top center most portion of the CPU and mostly pushed out to the edges. My theory is now that the two surfaces are slick as glass, they now lack surfaces capable of adhesion. The thermal paste basically slides off the two surfaces when compressed. I'm thinking of going back and ruffing the  two surfaces back up with some very fine grit emery cloth to give the thermal paste something to "grip". Any thoughts?  (BTW: Noctua NT-H1 thermal paste)

[Chris Pratt]

Yep. You've pretty much called it. The whole point of the thermal paste is to fill in the microscopic gaps, which does add the effect of adhesion. However, it's odd that you saw the temp increase. Theoretically, at least, if you could get the two surfaces perfectly smooth, at a microscopic level, you would not actually need thermal paste, because every nanometer would be in contact with the heat sink. If there's still imperfections, then the thermal paste should serve to fill them, no matter how fine.

[Moonzy]

Did you take off so much material that the mounting pressure becomes insufficient?

[The_russian]

21 minutes ago, Rocketdog2112 said:

the thermal paste was barely evident on the top center most portion of the CPU and mostly pushed out to the edges

If you sanded inconsistently you may have created high and low spots, which would leave spots without thermal paste. It's also possible you sanded too much material as Moonzy said, but I think that would require taking off quite a bit of material.

[Guest]

Some pictures would really......

[Rocketdog2112]

1 hour ago, The_russian said:

If you sanded inconsistently you may have created high and low spots, which would leave spots without thermal paste. It's also possible you sanded too much material as Moonzy said, but I think that would require taking off quite a bit of material.

I didn't sand, just polished with a paste like one would use to polish aluminum surfaces.

[Rocketdog2112]

1 hour ago, Moonzy said:

Did you take off so much material that the mounting pressure becomes insufficient?

I didn't sand, just polished with a paste like one would use to polish aluminum surfaces.