Question RGB fan runs irregularly!

[Mert57]

One of the 3 rgb fans on my computer is not working properly. To explain, it works silently and non-stop at first, and it suddenly turns slowly, almost to a stop, and does this loudly, after 1-2 seconds, it becomes quiet and smooth, then 5 seconds passes and repeats the situation I described. This is how it repeats itself. This does not affect the performance of my computer, but still, frustratingly, I could not understand how the fan suddenly slowed down and recovered. I would be glad if you help.

 

[JohnBonhamsGhost]

what make & model fan,
how is this fan powered,
what software are you using to control fan speeds,
how is fan control setup in the BIOS?

 

[Paperdoc]

I just posted this in another thread.

The NORMAL operation of a fan involves monitoring the fan speed signal for failure - that is, it stops turning and sending a speed signal. If that happens, the first reaction of your system would be to change the fan speed control signal to call for full speed to ensure it DOES re-start. If it does not, then you would get a fan failure warning screen and possibly a system shut-down to prevent overheating. But if the fan does re-start, then its speed signals would be set back to what it was before. If that is too slow, the fan will stall again and the cycle repeats.

What can cause this? Two things. IF the fan is old and worn, it may stall because of bearing friction even if the speed control signal sent to it is what would have been adequate when the fan was new. In fact, that same thing can happen to one of a group of seemingly identical fans if that one has slightly "stiffer" nearings OR is a different fan model. OR, the fan control system has been set to a minimum speed (for lowest temperatures and workload) that really is too slow, allowing the fan to stall. For this you may be able to re-adjust the fan control system to increase the minimum speed it is told to run at the lowest temperatures. See if you can make such a change in BIOS Setup for that fan.