I can't seem to slow this particular fan. I removed this fan from the cpu heatsink(extra one lying around) and attach this to this 4 pin thing on the motherboard labeled as "system fan". The problem is that this thing is going at 4000RPM. Its really loud.. speedfan won't work nor configuring in my BIOS. Anyone know how to slow this down? I thought I was sure I can lower the speed of this fan because it was originally a cpu fan..