Lapping My P4...

[burn'em]

I had read a lot about whether to lap the CPU or Not to Lap the CPU I finally got up enough nerver to lap my P4 1.5 and HS. I started with 400 grit finished with 1200. I stop when the copper started to show on the cpu. I couldn't get all of the small scratches out from the 400 grit (started to get nervous when the copper started to show!) but it was pretty shiny. I also lapped my swiftech 426 HS almost to mirror finish still had some scratches from the 400 grit. But look Shiny.
Running FAH 24/7 using Asus PC Probe The cpu ran 51c before.
It's only been running FAH for about Six hrs. cpu temp 47c. without any case fans just the power supply fan and a 80 x 38 Delta HS Fan.
The lapping took me about an hour for both I also used ASII before and after.

[outhouse]

pretty brave taking 400 grit to a CPU dont you think ? :) sounds to me like you took it down just a little to far i would be worried or careful when taking your HSF on and off as your core is a little thinner. From what ive found here lapping the CPU itself only results in a half to maybe a 1C drop in temps, i did mine but dont reccomend it, i think i started with 1000 grit and when it looked like chrome i quit [once the coating was gone] After i was only looking at maybe 1C cooler not really worth damaging the CPU.

[Gravity Man]

the only cpu I've ever had the balls to lap is a pentium 166 MMX. it took me 2 hours just to sand it down to where the lettering wasn't showing (it wasn't very flat at all) I still couldn't get the sucker above 280 MHz.