I have read across the internet, and there is a bunch of mixed thoughts on weather or not lapping your cpu and heatsink is worth it.
I was wondering what the folks at CF think of this.
My experience tells me its really worth it. My dell E520 with E6600 at idle after 4 hours:
After running Prime95 for an hour:
I have lapped the cpu and stock aluminum heatsink with 1200 grit sandpaper. Applied AC5, other mods include 2x80mm fans in the back, and the 120mm fan in my psu. From 35c idle and 52c load to 24c idle and 39c load, that is quite an improvement.