Does screw over tight decrease the efficiency of cooler?

[dr_bowtie]

I dropped my CPU temps by well over 10 C by lapping the base of my cooler and the IHS on my CPU. It's almost never *not* worth it to lap as long as you don't care about the warranty on your parts (for coolers it's nearly useless, for CPUs I guess you could argue that it's worthwhile to keep your warranty).

 

As far as over-tightening a heatsink - it's always a GOOD thing to get rid of extra TIM as long as you don't warp the cooler, board, or damage the CPU socket. Most coolers with screws that bottom out are pretty much designed to be tightened to that point.

 

 

Agreed...some cheaper coolers dont have the limiters built in and tightening them too tight not only squeezes out the TIM (which is NOT a bad thing) but it also warps the base of the cooler and thus actually lifting the center off the core...thus creating the higher temps as the cooler is no longer contacting the core....

 

on the cheaper ones the trick is to tighten it just enough to squeeze out the excess but not warp it and lift it...

 

I learned from experience that thinner TIM is better and checking the Contact patch helps...with the right contact patch at really tight cooler isnt necessary....just firm to hold it secure

[Bizzlenitch]

A tighter fit is certainly preferable. As others have noted the tighter the contact between the two surfaces the more efficient the transfer of heat from the IHS to the cooler. Just don't tighten to the extent that you warp your board. Some coolers' retention bracket designs eliminate this possibility, such as the Megahalems I've been using for a while now. It can only be tightened to a certain point due to the design of the heatsink and its mounting hardware. If I remember correctly, though, the old Zen FZ-120 cooler I used before the Megahalems would tighten to a point where board flex was possible. The first time I installed that heatsink I had loosen it back up a bit as it did cause my old IP35 Pro board to flex quite noticeably.

 

As a general rule, though, the tighter the fit between the IHS and the cooler, the more efficiently it will cool. Keep in mind, as others have mentioned, a little bit of thermal compound goes a long way. Too much and you'll notice the compound acting more like an insulator, promoting higher temperatures.