Noctua NH-U12P Intel/AMD Heatpipe CPU Cooler Review
 

With the NH-U12P, Noctua has brought one of those rare products to the market that can provide high performance cooling while still maintaining very low noise levels. The included low noise adapters are a nice touch and definitely add value, but even at full speed the fan is one of the quietest active CPU coolers I've come across.

http://www.tweaknews.net/reviews/noc...2p_cpu_cooler/