Hey there, i've always had a decent setup and never understood why i went from 350 fps (start of the game) to sometimes 120 (in hard teamfights).
I tried pretty much, everything, and heres the solution that changed everything.
Ive put a .jpg of what you have to do so its simple for you. Just choose the same settings as me.
Sounds created by champs & stuff are HDD reliants, mine was pretty old & weird, which gave me some troubles. So this is a nice nice fix. Hope it helped. Njoy :)