I bought a new Cooler Master CPU heatsink and fan to cool down my cpu. Problem is, the fan is only running between 1000 - 1500 RPM's, which is enough to make the BIOS freak out and say that the fan is not running fast enough. I have monitored the CPU temperature and it isnt overheating yet but it is getting fairly warm (around 67 C) The other thing about this fan is it has a 4 pin power connector and my mobo has a 3 pin cpu fan header. The fan plug is keyed so that it'll fit onto a 3 pin connector so i'm pretty sure it's connected properly. My question is does hooking the fan up to a 3 pin header have something to do with it running so slow and if it does is there a way to fix it so it runs at its rated speed?