Lapping a P4 IHS: any good?
 

If removing the Integrated Heat Spreader from your P4 sounds too extreme, then maybe lapping it might be an alternative.

Time to find out,

Victim is a P4 2.0 "A".
Here's how he looks unlapped ->

Using P600 sand paper to grind away the concave top of the IHS, and then proceed with P1200 to finish it off.
I used a small mirror as "flat surface", bought it at a local DIY shops for €5, pretty nifty :)

after lapping ->

Although it is no "polished" sample here, I'm wondering if there is any impact on temperatures under load...

CPU: P4 2.0Ghz - 1.54vcore
Env temp: 26.6°C
Cooling: Zalman CNPS7000-CU @ High
Thermal Compound: Arctic Ceramique


Load temps: 15min K7 CPUburn
before: 37°C
after: 36°C


there ya have it, gained 1°C by lapping the IHS; not spectacular. If you have the materials lying around it's worth it (free performance increase!) but don't go out and buy lapping gear because the return on investment is too low.

1°C is 1°C :)

nice, only thought the temp would drop more.

will do mine in a couple of days as well, good chance temperature drop will be more significant in an overclocked situation

Intel heat spreader is pretty flat to begin with. The lapping gets rid of the micro irregularity which, otherwise be filled with our AS5 with about 0.06 c/w representing about 6C at 100 watts.

On concave or convex surface lapping will yield much better result.

this IHS was pretty concave :)

you're forgetting how accurate your results are. your measurements are accurate up to 1°. a difference of 1° between lapped and not lapped doesn't exceed the accuracy of the results.

it's possible the unlapped CPU runs at 36.6°, so it's displayed as 37°. i'ts possible the lapped CPU runs at 36.4 degrees so it's displayed as 36°.

the temperature difference can be very small. as you said, the return on investment is too low. and you're voiding your warranty

thank you for repeating what I stated...