What is "lapping"?

[VBboy]

Many people say they do some "lapping" to smooth out the rough surface of their heatsink. What is "lapping"?

Is it literally rubbing the HSF against your lap? With or without pants on?

 

[Instig8r]

"Lapping" is a process that involves using various grits of sandpaper for smoothing the sometimes uneven bases of heatsinks. As a result of lapping, imperfections on the base of a heatsink are removed, and better contact with the processor core is achieved. In turn, the processor's overall temperature may be slightly reduced, and a lapped heatsink is much more aesthetically attractive than an unlapped one. Anyway, I hope this information proves to be helpful.

 

[VBboy]

Instig8r,

It was very helpful. Thank you for your response.

 

[Cherub]

Keep in mind that lapping a heatsink is meant to eliminate the tiny "valleys" that exist in the bottom of the heat sink where it meets the CPU core. It is because of these valleys that we use thermal compound, and the more the valleys are eliminated by lapping, the less compound needs to be used. Less compound is better because it is less conductive than direct contact.

However, just because a heatsink is lapped, even if mirror smooth, it does not mean that it is flat, which is the most important factor. This is why heavy sanding is sometimes required before the finer work.