I have a dfi dk x38 t2rb with an e8400 and put a thermaltake big typhoon (CL-P0310) cooler on it. I had the cooler on an older amd system with an Athlon x2 3800 and a Gigabyte Ga m55sli-s4 mobo. In the amd system, I didn't have to do anything for the fan to vary speeds (AMD cool and quiet worked very nicely). On this new system the fan just runs at full speed all the time. I tried futzing with it in speedfan and nothing. speedfan would show that it was changing the speed, but rpms (and the sound of the fan) stayed the same ~2000rpm. I built my comp with good airflow in mind, but even still, it would be nice if it were a little quieter when the cpu isn't under load. I also tried DFI's mobo utility and that didn't do anything to the fan speed. And yes, I double checked to be sure that my fan was plugged into the cpu fan slot on the mobo. Any suggestions on how to get the darn thing to vary speeds without popping the side panel off and manually adjusting the speed?