The Scythe Mugen and Infinity heatsinks are identical, except for a slightly more powerful fan on the former. As you saw in Frostytech's recent review, the Infinity heatsink is a quiet force to be reckoned with. That CPU cooler ranked in the Top 10 for its low temperatures and low noise output. The Scythe Mugen is no different, it just runs a little cooler still, and louder.
FULL STORY @ FROSTYTECH (http://www.frostytech.com/articleview.cfm?articleID=2215)