I just picked up a 60mm, 6200rpm (40cfm) fan for my 1800+ the other day. Previous fan was running at 4500rpm (unknown cfm). However, after installing it, I saw that the BIOS was showing the fan running at only 5300rpms, and as such, isn't doing anything to help my cpu temp. AIDA32 and Vcool also report the same speed. I don't think it's the fan that's damaged, because it looks just fine. Could the motherboard be throttling back the fan speed of the fan in some way, and if so, how could I change that? The fan came with a 4 pin for power, and a 3 pin for rpm monitoring.
System is a MSI 6380 v.2 mobo, 512ddr.