RTX 3060ti KFA2 - one fan constantly turns on/off and can't keep constant speed

[HarbingerAlter]

Hi,

about 2 weeks ago I build a PC (Motherboard - Gigabyte B550M DS3H, PSU - SEASONIC CORE GC 650W 80PLUS, GPU - KFA2 GeForce RTX 3060 Ti 1-Click OC LHR). The fans on GPU were working normally until week ago, when one of them suddenly started going on/off (video).

 

When I set the speed of each fan to e.g.50% in extreme tuner, one stays the same speed, but the other goes to 50%, then suddenly ramps up, slows down like it's powered off, and goes up again. The same thing happens both when idle and under the load. When the PC is booting, I can see that one fan immediately starts spinnig, second fan doesn't move.  I tried reinstalling NVIDIA drivers and plugging GPU again, didn't help.

 

Then the next day later on problem suddenly disappeared - after one of the restarts GPU started working normally, with both fans keeping consistent speed. For about a week there weren't any problems, unitl today the second fan again started going on/off.

 

I tried plugging GPU into another PC - exactly the same behaviour with fans, so it's most likely GPU. But I have no idea what could have caused it and why it worked fine for a week.

 

GPU fan keeps turning on_off-tM7Xi_eYsag-360p.mkv