So I upgraded my old 60hz monitor to a new 144hz Acer GN246HL. Now everything runs slow and windows won't recognize the monitor.
TF2 runs at about 20fps when it used to be able to run much much higher, although I can't remember the exact amount.
https://snag.gy/cKNYHi.jpg - it recognises the monitor here...
https://snag.gy/3ZuCTa.jpg - but not here - I can't change the refresh rate to 144HZ, unticking that box just lists lower frequencies.
Anyone got a solution? I'll post other information if anyone needs any.