I have a strange issue with Nvidia RTX 2080Ti lately. During the flight the fans are pretty loud but every few minutes or so they become completely silent for about a second and then start again. I assume they stop and almost immediately start again. I'm using MSI Afterburner to control the fans - I'm using this setup for about two years now with the same settings that NickN suggested. Nvidia drivers 536.23. This started to happen lately. Anybody else experiencing this? What could cause it?

IIRC, my (eVGA) 2080Ti card has a minimum 40% fan speed.  You can probably alleviate the start/stop behavior by setting up a custom fan curve that keeps the fans at 40% and then ramps up from there as the temp increases.

4 minutes ago, Bob Scott said:

IIRC, my (eVGA) 2080Ti card has a minimum 40% fan speed.  You can probably alleviate the start/stop behavior by setting up a custom fan curve that keeps the fans at 40% and then ramps up from there as the temp increases.

I'm not sure about that. I have the custom curve set up (from 20% to 100%) and it's definitely much quieter at 20% than at 40%. It also indicates values down to 20% in the live monitoring chart. 

https://imgur.com/a/5Ue96ji

The issue is that the card frequently becomes silent for about a second or so every few minutes - it's like stopping and starting back up again every few minutes which is very strange behavior that wasn't happening before.

OK, might be a different card.  But I'd still suspect that the PWM impulse at such a low setting might be so low as to not keep the fan spinning, which I believe is why the EVGA Precision software (an analog to MSI Afterburner) has a 40% floor on the fan speed.

Also, what's the significance of the dashed yellow line at 28% fan speed in your screenshot? 

I'm not really sure about the dashed line.

The issue appears when the card is working hard, not when the temps are low and fans are at 20% or 40%. This wasn't happening before, it just started to happen recently - no settings were changed or new drivers or software installed.

2 hours ago, Tomaz Drnovsek said:

I'm not really sure about the dashed line.

The issue appears when the card is working hard, not when the temps are low and fans are at 20% or 40%. This wasn't happening before, it just started to happen recently - no settings were changed or new drivers or software installed.

Well, in that case it sounds like either the fan controller on the card, or possibly a fan going bad and triggering the overcurrent protection on the fan controller.  In the slim chance that something got corrupted in your Afterburner profile or driver, it might be worth a clean uninstall of Afterburner and the drivers (using DDU or similar) and reinstalling.  Windows Update can install changes to the low-level driver platform that affects drivers. 

All that said, I strongly doubt it's software...sounds more like a developing hardware issue to me.  I'd open the case and watch the fans to see if they all stop, or if it's just one, as well as monitoring the GPU temp (to rule out a faulty temp sensor).