Now, by lapping you are reducing the overall mass of the heatsink, which would raise your temps a tiny bit.
Or do you only lap the CPU?
Lapping the lid of the CPU makes me too nervous. I'm not voiding my warranty for 2C.
dropped my old e8500 4-5C load temps
How do you know that was due to lapping and not just differences in the way you reapplied thermal paste and remounted the heat sink?
The internet is littered with successful examples of lapping.
Uh, that doesn't address my question in the slightest. Unless there is a test somewhere where someone mounted and unmounted his HS 10 times to get a sample average, lapped the CPU/HS, and then mounted/unmounted the HS 10 more times and showing the stats of the temps were statistically valid...
It helps, never hurts, to lap the surfaces. Assuming you lap them correctly of course.
It's become old hat for me though, I've probably polished around 10 cpu's by now, plus 10 HSF's.
Compared to how tedious and anal I made the process the first time, out of unfounded fears, the process is rather quick and easy now.
Temps can be off for any number of reasons. Your ambient temps may be different, you may be testing inside a case but the reviewers tested in the open, your specific CPU may simply operate at different Vcc's for any given clockspeed and thus be using different amounts of power and heat.
And you may need to re-seat your HSF, use a different TIM, use more or less TIM, etc etc.
Generally speaking, a good indicator that you have flatness issues and you need to lap is the difference in temps across the cores. My 2600K and H100 setup has about an 8C delta between Core 1 and Core 3.
I expect this will decrease to less than a 2C delta once I've lapped them (going by experience), the hotter core will decline the most, the coolest core might only decrease in temp by 1-2C. But the distribution will tighten up and the move to slightly cooler temps on average.
I have had one CPU though where lapping simply made no difference, the issues were under the IHS itself - either poor contact between the silicon and the IHS itself or the core on the silicon was just different than all the rest. As they say, you can't fix stupid, and some cores just can't be helped when it comes to their temp issues.
Lapping and/or delidding voids more than the standard warranty. It even voids the Intel Performance Tuning Plan. Regular overclocking on the other hand might be able to pass through standard warranty.Since you're overclocking, you've voided the warranty anyway,
Prolimatech does not condone any type of lapping done to the CPU or to heatsink base. Every Prolimatechs heatsink base is designed on a pin-point scale of how the base is to be flat and/or curved where its needed to be. We have programed our machines to machine the surface in a very calculated way. Any after-manufacture lapping or modding done to the base will alter the design, hence negating its performance factor as well as its warranty.
My opinion is lapping has less effect since they started putting IHS's on the CPUs
although I don't have numbers to back this up.
I've lapped several heatsinks for several different systems/components
temp drops tend to be minor 5c or less unless the surface was really bad
as far as thermal compound all products on the market conduct heat poorly compared to pure copper/aluminum (although still better than nothing/air gaps). I'd be interested in seeing a cold weld of heatsink to IHS or a nearly pure diamond paste just for laughs
D-14Complete waste of time and a great way to void a CPU warranty.
Just IMO...I would find other ways to shave 4C off temps..
If I had to lap my IB just for a small 5C difference, I might as well de-lid it. Both will void the warranty, one with minimal results and another that could make a big difference.
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...from the man himself:
Taken from this memorable, outstanding, epic... hell, just generally superlative thread. Lapping begins around page 3. And he mentions something about mounting pressure and it's effect around page 6 or 7, iirc.
Which considering your post count you may well have seen, but in case you missed it, enjoy!
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