Originally Posted by Retrospekt
Not 15c, not even close. Maybe 4 or 5.
It depends, I've lapped quite a few cpu's and hs's now, and it can vary. It depends how flat they are to begin with, and where
the imperfections are. I've had a couple cpu's (and hs's) that were concave or otherwise not flat, some are worse than others. Unfortunately cpu's seem to have a tendency to be concave, so the most important part (the center) is sunken down and not making very good contact.
I've had lapping drop me only a couple or few degrees, sometimes 6-8 or a bit more even, so far it's always
helped some. The more un-flat your surfaces are, the more it should help. Flatness is way
more important than to be shiney and polished. If you by chance had a perfectly flat cpu and hs, then lapping probably wouldn't help much. But so far, I have yet
to see a cpu or hs, which was perfectly flat.
Once I start the sanding and use the sharpie trick, I can always
see imperfection of the flatness, on cpu and hs surfaces. I did have one Big Typhoon (out of 4 I've purchased for me and others) that was dam close to flat. But then I had another BT that had a really uneven surface, it varies. Same for cpu's, my p4 prescott was ultra concave, others have been less uneven. Most important is to lap correctly
, if you don't do it right and with care, and you're not really
getting it flat, then you have nothing.