Weird Problem

[Spaghetti Shaman]

I never have this issue before and for context I have two monitors.
When I boot up the game on my primary monitor the FPS will drop to 6 but when I move my mouse to the second monitor and click on there the FPS goes back up to 60 and runs fine.
When I click back onto the game however the FPS drops back down again.

Even when it's running smooth I get crackling noises which from the discussions I read is a common issue.
Is there anyway to fix this? I'm so bummed out.