[SOLVED] GPU fans making a strange humming noise, but only on certain percentages rpm.

[Luke876]

Does anyone know what this is about?

I have a Gigabyte GeForce RTX 2070S.

For background:
It has a terrible constant revving up and down issue sub 40%:

View: https://www.youtube.com/watch?v=jeK7XVEFzq8

But over 40% this does not happen and so I just make sure the fans never drop below 40.

What really puzzles me is there is a different and strange oscillating humming noise (entirely different to the on/off fan issue above) at 40% which completely disappears at 41% RPM. Mysteriously, the noise comes back at 49% only to disappear again at 51%+ (after which point the fan is too loud to hear the humming noise, if it does return).

What is the science behind this? Am I missing something rather obvious?

 

[Ralston18]

Google "resonance".

 

[mortemas]

Two well known issues with Gigabyte fans. First, they do not start up properly from a dead stop, so as you have found out, you must ensure they maintain a speed just above your known problem speed (usually somewhere between 30 to 40% range for most users) or else they will repeatedly rev. Silent mode is still possible, but the starting speed from 0 rpm must be the 40% you have found to be ok for your card.

The other problem is there is no hysteresis, which causes a grunting noise when the fans rapidly waver between turning on and turning off due to the cut-in and cut-out temp being the same. I wrote 4 or 5 messages here in this thread about both problems:

https://forums.tomshardware.com/threads/strange-chirping-sounds-from-gpu-fans.3551418/#post-21446094

You can hear the grunting problem in the OP's sound clip in that thread. See the GPUz chart I posted there to see what is happening with temp and fan speed when you hear the grunting noise:

https://forums.tomshardware.com/threads/strange-chirping-sounds-from-gpu-fans.3551418/#post-21446463

Gigabyte's position on these matters is that it is normal.

You can work around it with custom fan settings.

 

[Luke876]

Google "resonance".

Can you ELI5? A lot of this is going over my head. I don't remember this issue with other cards?

Two well known issues with Gigabyte fans. First, they do not start up properly from a dead stop, so as you have found out, you must ensure they maintain a speed just above your known problem speed (usually somewhere between 30 to 40% range for most users) or else they will repeatedly rev. Silent mode is still possible, but the starting speed from 0 rpm must be the 40% you have found to be ok for your card.

The other problem is there is no hysteresis, which causes a grunting noise when the fans rapidly waver between turning on and turning off due to the cut-in and cut-out temp being the same. I wrote 4 or 5 messages here in this thread about both problems:

https://forums.tomshardware.com/threads/strange-chirping-sounds-from-gpu-fans.3551418/#post-21446094

You can hear the grunting problem in the OP's sound clip in that thread. See the GPUz chart I posted there to see what is happening with temp and fan speed when you hear the grunting noise:

https://forums.tomshardware.com/threads/strange-chirping-sounds-from-gpu-fans.3551418/#post-21446463

Gigabyte's position on these matters is that it is normal.

You can work around it with custom fan settings.

I cannot accept it given other manufactuers do not have this problem. I'm sending it back for an MSI Gaming X 2070S, which reportedly has not much coil whine (this card is loud) and no fan problems.