Noctua NH-C12P INTEL/AMD Heatpipe CPU Cooler Review
 

Performance wise, the NH-C12P is one of the best downdraft coolers available, and compares favorably with the better coolers on the market irrespective of design. In my book, the board cooling benefits of a downdraft cooler are well worth the minimal performance hit incurred. Opinions will vary on this point, and it will be up to the user to decide what's most desirable for a particular platform.

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