On 02/07/11 20:42, RedShift wrote: > > Actually it's possible a hardware monitoring module is interfering with the FAN speed control duties. Try preventing any hardware monitoring related modules get modprobed. See modprobe.conf how to blacklist modules. > > > Glenn Interesting thought Glenn, thanks. I've since gone back to CentOS-5.5 on the box (since it's not fully built anyway) and added the SuperoDoctor monitoring utility after resolving a couple of dependencies like SNMP and the correct kernel driver. I sent an enquiry to the Supermicro support folks, and they jumped on it right away, which impressed me. They wanted a screenshot of SuperoDoctor to try to analyze the problem. I don't think it's a case of a kernel module getting in the way because this issue crops up even during the BIOS boot process, and happens randomly if I run memtest86 as well. Sometimes the fans jump to light speed, other times not. I'm beginning to think it's either a bug in the latest BIOS or a sensor chip problem. Even when the CPU temperatures are reported as "Low", the fans run full speed most of the time. The exhaust air leaving the box is almost cool, so ambient temperature is ok. I'll give the Supermicro support folks some time to sort this out, since I'm still waiting for CentOS-6 anyway. Chuck