Enzotech Ultra-X CPU Cooler
 

If the Enzotech does top our cooling charts then it will certainly prove the down-facing coolers can perform at top levels. On the other hand, if the Enzotech performs similarly to other down-facers like the Big Typhoon VX, the Thermaltake MaxOrb, the Scythe Andy Samurai, and the Cooler Master GeminII it will simply further the evidence suggesting such designs are not quite as efficient.

http://www.anandtech.com/casecooling...oc.aspx?i=3022

You don't need to read the article to know the answer;)