Depends on how much contact the HSF has with the CPU. It will transfer heat, but not very well. Good thermal paste fills the microscopic voids in both the CPU heat spreader and HSF surfaces, and helps with the heat transfer. Without thermal paste, you've got metal on metal, and the heat transfer will be minimal, at best.
I wouldn't try it on a new system...but a crappy, hot system, like my old P4 2.8 system, sure. LOL
After thinking about this...if one laps both the CPU and heatsink to a super mirror finish (some 1200 grit sandpaper lapping for maybe an hour, on a precisely flat surface, that will create a perfectly flat surface on both items) it might conduct more heat to the HSF from the CPU. But that's a long shot.
I would guess it would still lower the CPU temp at least a little bit.
How would the temp be lower without thermal paste?
Well, being a heat sink wouldn't it still absorb SOME heat from the CPU? I've never looked closely at a CPU/HSF to notice, but how much of a gap is there without the thermal paste? Does the HS touch the CPU? I would think there would be SOME heat transfer just with the HS being close to the CPU.
If you lap your CPU, don't go too crazy. If you lap it too far, you'll ruin the CPU, since you'll pretty much expose the chip through the heat spreader. AND, once you start lapping the CPU, you pretty much void any warranties you have.
I would suggest to just lap the HSF, cause if you mess up, it costs you $20-70 bucks, compared to $70-1k.
Also, it's quite time consuming. Don't think you can just rush it, or you might start rounding the edges, and worse case, you'll just ruin the HSF surface.
How do I know this? I did it, and many of my friends have done it. We trashed at least 1 CPU (not me) and several copper blocks off heatsinks.
Well.. I don't think I'd ever attempt lapping the HS. I would be more worried making it lopsided.
Using thermal compound works enough for me.
But I thought it was interesting info. I remember Wusy talking about it.
Oh, I've seen some crazy folks during my case modding days.
I remember seeing someone lap his CPU till it looked like a little mirror. It was pretty cool, but looked just way too risky for me. My buddy tried it, and he actually lapped thru the HS. LOL. The look on his face was hilarious.
I would simply lap the HSF unit. And if possible, remove the copper/aluminum base and lap just that. I haven't lapped a HSF in about 2 years, since I just got lazy and wanted the system up and running as soon as possible.
Heck, if someone really wants a cool CPU, just use a phase cooler unit.
What good is a heatsink and IHS for if you've got wet'n'dry sandpapers, 400, 600, 800, 1000 and 1200grit left over from 2003?
All except Swiftech and Scythe products.
That's why I can use the superior Arctic Silver Ceramique/MX-1 while you folks have to use the overpriced&expensive AS5. :tongue:
And how much time did you put into sanding? Time = money and too much time on sanding will cost you (opportunity cost) more than the price difference of AS5 vs MX-1. :roll:
For companies and businesses, yes, time = money.
But for computer hobbyist and/or enthusiast, lapping is nothing more than squeezing out more performance via better heat transfer.
I mean, people who mod their cases by cutting or even building their own case, aren't wasting time, in their minds. They're simply trying to be different and make something they want (or can brag about).