IIRC the extra pin on a 4 pin motherboard header may report if the fan has totally stopped, like a failure line, to tell the mobo to shut the CPU off. I've got an old 4 pin fan here from a '94 vintage ...

I've been installing a few case fans onto my new PC, and I had a fan that connected via the three pins on the motherboard. I've moved the three pin fan to a new location but I can't find any other ...

Computer motherboards sold at places including Best Buy and Amazon have been recalled because the capacitor “was installed in a reverse position which can lead to a short circuit, overheating or ...