ROG Thor III Fan Speed ramping up whilst sitting in desktop with chrome and outlook open

[Sco80]

Hi there, I hope you're all well.

My ROG Thor III (T3) 1600 watt power supply fan is ramping up and down every 5 minutes or so whilst sitting in desktop with chrome and outlook open. It has only started doing this yesterday. It never used to do this and it is not hot in the room. I have had this PC benchmarking for days on end and never heard the power supply fan kick over once and I am running a 5090 astral GPU. I am running the power supply in 0db mode. Is this normal behaviour? It is highly annoying that it is doing it as it is on and off whilst in desktop and I cannot work out why it is doing it as there is nothing in task manager utilising the CPU. I had a look at the power supply and the fan is not spinning at all.. shouldn't the fan be at least spinning slowly? The power supply is only a few months old and the PC is clean, no dust as I clean it regularly with a little blower.

Is it possible than chrome or outlook could be causing the power supply fan to ramp up? Is there a fault with the power supply? Should the fan be spinning in 0db mode? In turbo mode the fan does spin slowly but once in game you can hear the fan really going for it which I do not like as I prefer a quiet system. I do understand of course if a component gets hot it does need to cool but seeing as this never happened before I am not sure if this is expected behaviour or not. 

Thank you for any help and sorry for the long post. 

[Sib3riX]

I own same PSU for 3 months now and didnt experience what you describe. Go to nvidia panel settings and restore settings to default. Fan should kick in after psu start to consume 480+ watts. 

I would also try to turn off pc and unplug from wall then press power button to drain all power in your pc and try again. 

[Sco80]

Hi Sib3riX. Yeah its weird AF how it has started doing this all of a sudden. I have applied my under volt in MSI to start when windows starts and I have changed prefer maximum performance to Normal in power management mode. Coincidently windows updated recently and it has started from that.. The install is quite old as well so maybe I might need to reinstall windows if it continues. I will also install latest nvidia drivers and see. Is there anything else you can suggest I can do to reduce power consumption in windows? I am currently idling at 220 - 230 Watts. Actually what are you idling at in desktop if I may ask? TIA 

[Sib3riX]

My idle power is around 160w in total with 5090 astral lc running without any power profile just using nvidia default. Windows profile is set to prefer max preformance.

For a test boot your pc into bios and let it sit there for 5 minutes then try to see if you can hear fan turning on/off if it doesnt happen its probably something weird happening on windows/software side.

[Sco80]

That sounds about right if you are not running a big display like I am. I lowered my refresh rate and it dropped to about 180-190w. I think the other problem is in my case there is no air flow around the power supply. It is in a lian-li 011d case and the power supply is in the bottom right hand corner of the case tucked away. We have just entered into Spring here so the ambient air temperature is up a couple of degrees so I am guessing heat may be building up in the corner of the case? Not sure. Going to heat the system up later today and also try your suggestion and see if it is a windows issue also