I just recently finished a lil project, which many of you would call crazy. I over many builds have seen the benefit of lapped heatsink to a non-lapped heatsink. So I got to wonder about lapping the heatspeader on a processor. I read three guides and the results turned out ok. First I'll say that this was not on my new pentium D (i am not that crazy Yet), it was on a celeron D 2.4GHZ. Second this takes a long time(wanting to be careful, and going through all the grits: 220, 320, 400, 600, 800, 1000, 1500, 2000, 2400, 2800 really hard to find). After the lapping you'll find must of these heatspeaders are made of copper. After lapping the heatsink (with all the same grits), I found a dramatic drop in temps(most like do to the flatter surface on both Heatsink and Processor) the Idle temps dropped from 39C idle to 23C 8O . This was with an intel stock HSF that i lapped, I just wish I that the mobo I have for this rig could overclock. Yet again this was an older rig I didnt care if I messed up, I don't recommend this unless you have alot of time and your very careful. The processor took me 2 days to lap(I was going very slow to be careful not to damage the CPU), the Heatsink 5 hours.