Monitor suddenly lagging on desktop, doesn't apply for games

PCgamernut

Honorable
Oct 1, 2013
16
0
10,510
When I play Splinter Cell: Blacklist, on ultra settings with 4xMSAA (4 being the highest) I get a good 65+ fps. When I quit to the monitor, after a couple of seconds of nice crisp 120 fps, because I have my refresh rate on 120Hz, it starts lagging like crazy, making my PC un-usable. This PC is less than a month old and it runs A GTX 770 MSI Lightning 2GB GDDR5 VideoRAM, an i5-4670k running 4 cores at 3.4GHz and up to 4.5GHz and 8GB of Corsair Vengeance RAM. This problem is just horrible, my monitor is the AOC G2460P, a 1080P monitor with a refresh rate of 144Hz

Please help guys