DeadlyMercury

ZoranC
Which to me strongly points in direction of PX1. It is either interfering with fan speeds or it is interfering with readout of fan speed. I can’t say which one of those two it is as I don’t have a way, nor knowledge, to find out what fan was actually instructed to do nor what are its actual RPMs.

Well, it actually stop fans, not just read fan speed wrong. And with default update interval (1 second) it means that fan is barely spinning and that leads to overheating.

 
That is what I too am suspecting but don't have a way of proving because even if rad fan is not stopped every second but never moves beyond that magical number of 800 rpm (when PX1 is not running and it is card controlling it) I still get similar temperature rise.
 

DeadlyMercury

ZoranC
So in the end I gave up fighting with EVGA (for now) and did exactly what you suggested I should do: I am using OC BIOS for driving of the fan 1 so I don’t have to ever hear that grating sound and rad fan I’ve connected to SYS2_FAN on mb at 80%. Even at 80% Noctua is still very quiet, quiet enough that at the moment I can’t notice it / it doesn’t bother me, yet TimeSpy Extreme temperature doesn’t exceed low 50s C.

So if you gave up that way - you actually can use msi afterburner to control vrm fan (custom fan curve works fine there, but msi afterburner cant control rad fan) and even switch back to normal bios to get that zero rpm at idle.

 
Thank you again for the advice :) As of now I don't see need for Afterburner, VRM fan seems to be behaving fine when controlled by OC BIOS keeping temperatures at the good level, but it is good to know what I might be able to do if something changes.