At the stock 2.8GHz the Kuhler H2O 620 cooled the Intel Core i7-930 to 57.75*C, a very nice 21.75 degrees cooler than the stock Intel HSF. It is only 1 degree warmer the Corsair H70; which has a bigger radiator and dual fans. The Kuhler H2O 620 is also 2.75 degrees behind the CoolIT Eco ALC240, which has 240mm radiator, but beats the CoolIT Vantage ALC by 3 degrees. So the Kuhler H2O 620 is beating water kits with the same size radiator and hot on the heels of the kits with bigger radiators.
After bumping the system up to 3.5GHz the Kuhler H2O 620 is still doing well. Coming in at 64*C it is in the lower 60’s, and only 3.25 degrees behind the Prolimatech Super Mega. The Kuhler is also still ahead of the CoolIT Vantage ALC by 3.75 degrees and behind the bigger radiator kits (Corsair H70 and CoolIT ECO ALC 240) by only 1.5 degrees.
Really turning the heat up, we have the system running at 4.0GHz now. The Kuhler H2O 620 comes in at 74.25*C, on par with the CoolIT ECO ALC 240 and better than the CoolIT Vantage by 2 degrees. The Corsair H70 still beat it by 2.25 degrees; again, there is a bigger radiator and dual fans on the H70.