Thread: Lapping FTW
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Old 03-17-09, 09:10 PM   #51
Join Date: Mar 2004
Posts: 15,486
Default Re: Lapping FTW

Originally Posted by Bman212121 View Post
I'd also say it could have to do with what type of TIM you're using. If your TIM is too thick that it cannot stay in the holes I'd try some different stuff. Using Zalman STG-1 I can get the paste incredibly thin and still have full contact.

@mailman2: Nope I definitely haven't been lapping procs very long. But I'm still going to argue that I could achieve better results from a smoother finish. I have a few ideas to test my theory with.
the only theory you need is that

heat flux = driving force / resistance

resistance = sum of individual resistances
driving force = difference in temperature

heat flux (aka heat removal) is higher for direct contact than it is with TIM in the interface (which is an extra resistance term). so a smoother finish increases contact and minimizes TIM resistance, hence better heat transfer.

transport fundamentals 101...

this also explains why you cant cool something below ambient temperatures without doing work.
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