I don't think time is relevant. Did you get a patch or install some program? update graphics drivers?
Verify integrity of game files through steam.
Do you have any mods installed? - if yes, uninstall them.
Make sure your power profile is set to maximum performance and make sure there's no extra settings in Catalyst Control Center.
Also, check your temperatures please, cpu and gpu both (hwinfo, hwmonitor, msi afterburner, etc)
i verified the integrity 3 times. i do have mods installed, ill uninstall those after i get home, and i have a cooling pad on my laptop but it does get slightly hot when i play World of Tanks, where would i check the temperatures at?