Question Does anyone know what’s wrong with my fan?


It appears the middle fan is stopping and re-starting constantly. A few things can cause that. First, though, background: any mobo fan header monitors its fan's speed for failure - that is, stalling. If that happens the first action is to send it a signal to run full speed to get it started. If that does not work, you get a fan failure warning on screen. If the fan does re-start, the signal to it is re-set to what it was before. But if that signal is what caused the stall, it will continue to happen.

1. The fan may be faulty. Shut down your system. With a finger, go to each of those fans and spin it. Each should spin easily and then slow down slowly to a stop. Is that middle one different - stiffer, or stops very fast?

2. IF those fans all are connected to different separate mobo fan headers, check the configuration of each header in BIOS Setup. They should all be the same.

3. Whether that one fan is on its own header, or shares a header with the others, you may have the header configured to operate it at a very low speed especially at low temperatures so that it is just on the edge of stalling. Among several identical fans there is some small variation in stall speed, and MAYBE that one is just slightly more prone to stalling. If you thnk the fan is not faulty, change the header's configuration to set the low-temperature minimum speed a bit higher to prevent stalling.