Testing / comparing : Intel D975XBX2 / Asus P5B DX ***56K WARNING***

[minsc_tdp]

4 pin fans aren't backwards compatable with 3 pin headers but 3 pin fans ARE backwards compatable with 4 pin headers.

The motherboard doesn't care if there's something plugged into the processor fan header or not. I just unplugged mine with the system running with no ill effect.

Try it.

EDIT: Wait, are you saying that the fan is getting its power from the 4 pin molex connector on the motherboard?

I believe you. After coming to my senses I realize the fan or controller must be broken.

And no the fan power is on it's own big 4-pin molex straight into the PSU. Only the yellow line (on a 3 pin connector with 2 pins nothing) is on the mobo.

Yeah, I just plugged the FM121 cpu fan into a different molex up near the DVD drive and the controller worked again momentarily, dropping to 1600, but seconds later jumped back to 2000. So I'll just have to leave the controller at max until I can try another controller or replace the fan.

BTW GTJ, you are a true hero for continuing to support the newbs like me coming late to the party long after getting your own board stable. Your legend will never die.