There is another thread in the motherboard section regarding the ASUS PC Probe II and some issues with detecting fan rpm of the PSU and case with the ASUS A8N-SLI Premium, I also have this problem, I've read that some PSU's don't have RPM sensors, is that the case with PC P & C? I tried several programs, Everest Home, Speedfan and the latest version of Asus PC Probe II and I can't get a reading off of my PSU. I also read that some motheboards can't detect RPM's under 2000 and default to 0. "Fan Speed Monitor connector (3-pin) providing real time rotational speed of the power supply fan to the system. Most motherboard has at least one extra 3-pin fan connector in addition to the standard CPU fan connector.Fan Speed Monitor connector does not have to be attached to the motherboard in order for the power supply fan or the AFC function to work. Some motherboards are not able to detect the RPM lower than 2000,When that is the case,it may show the RPM is "O". " I don't think my PSU has this?