For anyone else having this problem: Black Ops 2 automatically runs with Intel HD integrated graphics. To fix this, go to your NVIDIA control panel and switch to the tab "Manage 3D settings" and switch the preferred graphics processor from "auto select" to "High performance NVIDIA processor".
If I remember correctly there should also be a application mode for Black Ops II for nVidia. Haven't used an nVidia card in a little over a year but I know AMD (ATI) mirrors the same concept and they have released one.
There is information found HERE
from nVidia on some common tweaks to help it run smoother.