Hum from games

Hi all I have tried a number of sites to find an answer to a nagging problem. I am hoping someone here can help! I am using cubase 9 on a mr816csx with a pair of hs80m monitor speakers. Recording and playback through the mr86 and cubase works fine…if i play songs through itunes of media player the songs sound great from speakers or headphones plugged into mr816 you tube plays fine …where the problem is is when i am gaming I play wow and when i enter server i hear a loud hum form the speakers and headphones…if I shut speakers off (power) the hum goes away in the headphones. I have a 980ti graphics card. my computer …monitor mr816 is on a separate circuit …my speakers are on a separate circuit both run directly back to electrical service. I dont have bucks to just start changing stuff so I am looking for some input perhaps someone here you had or has same problem?
Thanks Gejodi

Put it all on SAME circuit so you have a common grounding point.

Are the monitors connected via balanced lines?