Power from speakers connects to the same plugs as my PC. My powered speakers have both quarter inch jack and and XLR audio connector. My solution was to connect speakers to a pre-amp box with a balanced audio cable. I’ve read on the web many people have similar issues and trying to solve it with PC power management and other tweaking PC settings with only partial success. Noise ranging from high pitch scratchy sounds to a high to medium pitch buzzing or clicking.
I had an annoying interference sound whenever I would move mouse or any SSD or CPU activity (aka while typing on keyboard or starting any program) interference radio signals and feed them to my speakers.
Output from Pre-Amp goes to my Self-Powered Speakers that is plugged to the same power outlet as PC. My system is this: from my PC -> USB connected to a small Pre-Amp on my table.