Lapping my CPU: Questions

elpedro

elpedro

elpedro

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So I've ordered a new case and the Corsair H50 cooler today. I've had my Q6600 up to 3.6GHz albeit at quite high temps and voltage to the extent where it was bordering dangerous (85C full stress) so I've kept it at around 3.4GHz.

That was with an Akasa Evo CPU cooler which cost me around £30 over a year ago. I'm hoping the H50 will be signifigantly better so I can have a nice stable/cool 3.6GHz overclock... potentially even higher!

My question, is it worth lapping the CPU and how hard is it to do? I understand its a matter of using a few different types of sandpaper but I'm not too sure how far you go down and if the benefits are worth it?

Cheers.
 
Benefits were slight for me, if I recall my temps dropped by 2-3c. Lapping kit price was £10ish and took about 1hr to achieve a nice shiny surface:




Old cooler in pic I'm using a Noctua with my Q6600 now. The new Noctua isn't lapped this change reduced my temps more. The cooler in the pic was a Thermalright Ultra 90
 
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From what I have heard from people on here, you start with the most course sand paper for 10reps, then turn 90 degrees, repeat until you have done a full 360 degrees.

Then use the next finest course sandpaper for another 10 and repeat until you get to the most fine sandpaper.

Dont apply much pressure, just let the weight of the motion apply the pressure.
 
To me its not worth voiding the warranty on the cpu to do it, that said if its out of warranty then go ahead, but temp gains won't really be that drastic.
 
The way i see it, unless you can achieve nearly perfect flatness then the rougher the better. It's just more surface area for the thermal compound to fill.
 
Think most Ive seen people claim is a 5C decrease in temps, not bad, but I personally wouldnt go doing it to a brand new i7 or whatever! Like bifday said, if its out of warranty already go for it, its a bit of work, not that expensive and should reduce your temps a bit :)
 
Cheers guys, I thought the temp improvements were better than what you've stated. The chip has just under 2 years warranty left so I think I'll give it a pass and just see how the H50 does tomorrow when it arrives.
 
I dropped 5-6c from my old q6600, TRUE lapped as well, didnt bother with my q9550 and definitely wont with my i7. I wasnt particularly concerned about the q6600 as id had it a while.
 
Superewza said:
The way i see it, unless you can achieve nearly perfect flatness then the rougher the better. It's just more surface area for the thermal compound to fill.
Click to expand...

Uh, you do realize thermal compound insulates it don't you? The only difference between using thermal compound and glue, is that TIM insulates it less than glue. Any kind of smoothness is better than it being rough. How much better is debatable, but still better.
 
Somebody on here the other week was claiming that you should see around 8 to 10c difference in temps when you lap both the CPU and HSF..

I didn't think that you would see that much of a drop tbh.
 
If gains were in the region of 10C then I would have thought the heatsinks came pre-lapped for a slight premium, CPU's wouldnt be as it leaves nowhere for the information to be printed :rolleyes:
 
You need to check how flat both surfaces are then assess if you need to lap either of them.

If they are flat already you wont see a worthwhile benefit from lapping.

However if you find one is concave/convex, or both are, then you could see a difference of up to 10C.
 
yes, a temp drop of 10 degrees is quite achivable, but only if you lap both dead flat to each other.......... but you wont get 10 degrees if both are already relatively flat before lapping....maybe only 3 to 5

you might actually see a temp rise by only lapping the Cooler, if you've lapped the cooler...you should really lap the CPU.....this is because many coolers are domed on purpose to match the CPU, removing this dome makes the contact area even worst.

once both are lapped, the thermal paste will squidge out the side... regardless...because perfect flatness means, that under pressure, the paste will be driven out the sides leaving only a very thin film between the 2 surfaces...much more so than unlapped.

it'll look like you've forgotten to apply the thermal paste :eek:
 
I had to lap coolermaster gemini 2 yesterday, it looked like the surface of the moon, something had happened to its surface and it was all scratched. They did put the protective plastic sticker over though!!!
 
sticky link

Also flatness is what you are after not shiny/smoothness.
A metal rule placed across opposite corners of the ISH will show flatness
or Marci grid test - the two links at the bottom of the sticky above - NOTE both are mirror smooth!

Flat and microribed is MUCH better than shiny and concaved.

I should add that some TIM are better with lapped surfaces (liquid metal) and some are better with flat ribbed surfaces (AS5).
A few like MX-2 work just as well on both.
 
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I lapped my Thermalright ultra 120 and Q6600 and got an improvement of about 5 degrees. The main improvement of the lapping was the fact that I also managed to get from 3.2Ghz (my previous highest stable overclock) to 3.51 Ghz.
 
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