17 CPU water coolers test: better than air cooling? @ Hardware.Info
 

The best cooling performance is achieved by using the Corsair H100i, a water cooling kit that can be controlled to the smallest of details by enthusiasts thanks to the included Corsair Link software. The NZXT Kraken X61 cools about the same - better when used on a Socket 1155 - and can work significantly quieter than the H100i. Therefore, the X61 is in our opinion the real winner: obviously better maximum cooling performance than the best air coolers, but it still performs well even with limited noise production. Because the X61 has a 280mm radiator, it only fits in a limited amount of cases; it's also an expensive kit. The best 240mm kit that can perform the 30 dB(A) test and performs only slightly worse than the X61 is the Thermaltake Water 3.0 Extreme. Both are awarded a Gold award, the H100i is awarded Silver.

http://uk.hardware.info/reviews/5981...an-air-cooling