Applies for Nvidia Users for now
Disclaimer: I do not guarantee this will work, I am not responsible for any bad things happen to your computer. However for me this solution works pretty well.
It seems like Nvidia did not manage to detect Black ops 2 as graphics hungry game, so it uses the built in Intel graphics, which is for power saving and low performance. To fix this we need to activate the Nvidia graphics card for this game to unleash its FULL POWER!
1) Delete all the files in directory
*steam installation folder*/steamapps/Call of Duty black ops 2 (whatever)/players
This is to ensure no previous graphics settings are left behind, pretty much like resetting.
2) GO TO NVIDIA CONTROL PANEL, “Manage 3D Settings”
3) ADD the black ops 2 .exe(s) (for example, t6sp.exe, t6mp.exe…) files into the list, shocked when you see your game runs in integrated graphics right? hahah!!
*If the graphics card chosen for the game if high performance nvidia, that means this fix is not for you, go and continue your googling.
4) Change the option to High Performance Nvidia card. Set the setting to all black ops 2 programs.
In my case, it fixes the problem!!!!
Do drop a comment below and let me know if the fix works!