Installed the x40 a few hours ago and it is working great on my antec 300 case.
My CPU is Phenom II x6 1075t
Due to the right fit I could not have the entire unit in the case or the radiator would touch the fan header on the motherboard, so I removed tome of the mesh on the top of the case, then installed the fan on the outside of the case, and the radiator on the inside.
With prime 95, my temperatures will jump up to around 75-79+ C on my sunbeam tech core contact cooler.
And as a temporary fix for the sunbeam cooler if I tape the sides of the cooler and also the top to make a duct out of the side intents, the temperatures drop from 75-79+ C, to around 69C at full load.
With the kraken x40, the temperatures have dropped to around 45C under prime 95 (though the motherboard temperature sensor reads a higher value.
PS while taping the core contact cooler does significantly drop temperatures, it does not last long before the tape starts coming off.
but if you can force more of the air to go through the entire heatsink, the temperatures drop significantly.Edited by cutepuppy671 - 8/15/13 at 12:32pm