Finlayjohn :
The humming sound is fairly quiet but since its new i want to know what it is, it only does it on gat since for some reason i cant run it, even though my rig can gta in 4k,i have no hdd so thats out.
My psu is a RM650x (2018)
Humming noises are ussually caused by fans.
The first thing I would try is the power supply.
I' ve read online several complaints from Corsair Power Supplies´s users about a humming noise coming from them. Corsair technical support tells them to try flip the PSU upside down, so that sound stops. Check if that works ( I guess you can claim your warranty in that case though).
If that is not the case I would suggest troublleshooting all your system case fans, cpu, and gpu fans, to see where the problem is.
Since you don't have HDDs I don´t know if that sound could be from another component