Originally posted by: GalvanizedYankee
The base of the SI-120 does not need lapping. It is silver in color because it's been struck
with nickel inorder to facilitate soldering the aluminum fins to the copper heat pipes.
Some may dispute this but the nickel is so thin, it's effect on heat transfer is a non-issue.
It needs no more than 50cfm to do it's work. Your call on a fan but be aware, clear plastic
LED fans offer more dBA than black plastic jobs. I dislike the Panaflos made in China, known
here as Chinaflos

For a CPU HS fan it's a plus to use one with a tach/sensor feed wire. Not all three wire
fans offer this option, so be sure your selected fan does.
Throwing budget out the window as I often do for PSU & CPU fans, this is what I would use.
The two most important fans for a system are CPU first, PSU second.
http://www.sidewindercomputers.com/de12trbllows.html
Finding a good 120 fan for <$10 that has a tach/sensor wire will be a challenge. I know
of a few but they are>100cfm.
...Galvanized