The volume overlay is the little volume bar that shows up on top left of screen in windows 10 when you change the volume on your speakers/headset.
My frame rate was cut in half intermittently for the last week or two until I disabled the volume overlay.
To fix I followed instructions from howtogeek to disable the overlay, basically by installing a small program that runs on startup to get rid of it. Sadly I couldn’t find a windows setting that would disable the volume overlay, if someone knows of a setting please reply with instructions!
I can’t include a link, but you can google “how to hide the volume pop up display howtogeek” and that will get you there. Note that the google feature snippet shown that says “Click the tray icon to toggle the volume display on or off. It’s that simple. If you don’t want to see the system tray icon, you can just hide it by dragging and dropping it to the left of your notification area icons.” is referring to the version of the app where it hangs around on the start bar.