If you are going to sand it you need to use wet dry (automotive)emory paper in grits ascending to 1000 or 2000 grit. You want to sand it against a very flat surface and not in a swirly pattern. Go in one direction and get rid of any concave or convex warping in the bottom of the heat sink. Once it is flat, polish it until it reflects like a mirror. Personally, I don't do it wet. I just clean out the metal dust about every 10th pass.
CPU Heat Sink Lapping Guide
The Coolermaster dp5-6I31D-01 is probably not adequate. You probably have a thoroughbred B core which runs a little hotter. Info on -- AMD - Athlon - Thoroughbred That chip does not overclock well, so be sure the voltage is 1.65v. If it is overclocked, and it is stable, except for the heat, then you definately want a better CPU cooler.
CPU Heat Sink Lapping Guide
The Coolermaster dp5-6I31D-01 is probably not adequate. You probably have a thoroughbred B core which runs a little hotter. Info on -- AMD - Athlon - Thoroughbred That chip does not overclock well, so be sure the voltage is 1.65v. If it is overclocked, and it is stable, except for the heat, then you definately want a better CPU cooler.