Question Microstutter after new GPU installed

[Kuplungúr]

Hi!

So yesterday I bought a 6900XT red devil ultimate from Powercolor. Previously I had a 2080s. I ddu-d the nvidia drivers after installing this beast which requires 3 psu connectors instead of 2 (8pins).
Since Windows first booted (latest win11) I have this microstutter. Everything freezes very briefly in every ~10 seconds, even mouse cursor or an Instagram reel. Now I also hear the regular "new hardware plugged/unplugged" sound when the stutter occurs. Super weird.
My psu is a tx750m. It comes with 4 8pin connectors in total so one would think that is enough.
It does not stutter in bios but I guess that's different. Tried to ddu and reinstall drivers, updated armory crate...
Please help! Is that the psu? Or something else?
Specs:
Asus z390-h gaming
I7-9700k
Corsair tx750m
2 m.2 drives
2tb Toshiba had
1 Kingston ssd
1 pci-e USB hub
Cooler master m240b aio

 

[kerberos_20]

frequent device connect/disconnect could make what youre experiencing, most likely some USB device is acting up

 

[Kuplungúr]

frequent device connect/disconnect could make what youre experiencing, most likely some USB device is acting up

Ok, it turned out that my USB hub in a pci-express port was acting up. Unplugged that one and the stutter stopped. However... the GPU is still acting weird. Yesterday my pc froze like 4 times while playing Valorant (hardly a demanding game, really) and only hard reset helped. Then I tested it out in RDR2 (a demanding game) and it was the following:

• 120 fps on ultra while the gpu had a very loud "im calculating" electric noise, similar to electronic equipment which are dimmable (resistance can be changed). All GPUs have this sound but this one is like 3 times as loud, annoying.
• random drops in framerate to 50 while the GPU usage also went down from 99% to 55%... but due to no reason.
• Monitor turning off and on again, while the AMD graphs showing that Wattage and usage both cranked to 0 for a split second. It basically turned off.
• GPU being 80°C and some other part (Crossing?) being 100°C which I find too much, especially that fans are working quite hecticly.

So it's ultra weird and very unreliable