Dual Monitor FPS issues

[Whiskerine]

Just got two monitors and when playing CSGO my FPS dropped a ton, it now averages around 40 instead of the usual 150ish. How do I fix this?

I have an i5 6660
AMD RX 470
16 GB of Ram

I also have windows 10

 

[Whiskerine]

Like a retard I made the same mistake I made a year ago when moving computers. I hooked my cable up to the wrong slot and so it wasn't using my GPU on the right monitor so it everything would run terribly.