Slowdown after changing my monitor

[AreaOfEffect]

I used to have an 18.5 inch monitor then switched to a 23 inch, My game felt so smooth before and no lag at all but after the change the game really slowed down. How can i fix this?

[JaoSming]

did you increase the game's resolution with the new monitor? if you did, that will cause performance issues if the computer can't handle it

[AreaOfEffect]

Nope. But i did increase the monitors resolution on the desktop settings.

[Patr1ck]

Changing a monitor has no performance impact. It has to be something else.

[AreaOfEffect]

Okay so what do you think caused this?I have an Radeon HD 6790 video card.

[Andrew]

Have you tried running the benchmark again or adjusting the in-game settings at all?

[AreaOfEffect]

I remember having 100+ fps using Fraps, so its like 60 in 2k benchmark. Now my 2k benchmark is only 22.