I decided to buy a pack of fine assorted wet/dry automotive grit papaer, and went to work. I lapped the IHS down to the copper, cleaning with rubbing alcohol frequently, and it looks so pretty. I also lapped the SLK900U, which is done to a mirror finish, but after awhile, the silver particles get in the micro-groves. Remember copper is actually a porus material. I lapped it down, and it looks even better then when I got it.
Perhaps the most surprising thing I found was the uneven surface of the Intel P4. The corners had significantly more material on them. I used a L-ruler to ensure the surface was flat and then wrapped the paper around an perfectly flat edge and went to work. Obviously this is critical, because you want a flat surface. But as I said it took quite a while for the corners to get down. This is bad, because with the outside edges contacting the Heatsink, there forms a pocket where hot air would become trapped. No good.
Prooof is in the sanding. Yesterday in the same Ambient temp (my air conditoned room) my overclocking temp was 45C to 49C at 3.6GHz (300FSB) today same ambeint temp, and OC conditions, and the temp's are now 38C, and haven't gone above 39C. That's 6C to 11C temp drop! Next I'll be removing the IHS all together. Intel uses thermal paste which is not of the highest quality, and of course they don't it spread thin and even as we would, but simply shoot a dollup of it on the core, and epoxy down the IHS. The hole is for gases to escape or the thing wouldn't adhere correctly. The latter is speculation. But they do use way too much paste, and as everyone know's this can become as much as a deficit, as a dissipation method. I shopuld have took pic's but i was too lazy. I'll take-em tomorrow, and add them to this post. The cip looks much better lapped.