Measured gpu usage with afterburner, questions

[NedLynch]

I use afterburner to overclock my EVGA gtx470 at times without any problems and of course in games I am displaying to what percentage the game uses the gpu, together with clockspeeds and temp.

Overclocked or not, afterburner shows a gpu usage of great variety in flight, around 50% (maybe lower) to 80% ish at framerates that would make you think, if the gpu was being used at 99% I'd have more fps, one side effect is that the card stays very cool in flight (64 -66 celsius).

Overclocking the card seems to have only a marginal impact on in flight fps contrary to other games ( used Crysis2 to test the overclock I had further and with high res texture pack and dx11 I had 55 - 75 fps @ 99% gpu usage, 40 - 60 fps @ stock speed ).

My question is, is this the game or maybe the current nvidia driver (280.xx) and is anyone else observing low gpu usage?

My setting in the nvidia cp is to prefer maximum performance on the card.

I am also going to try the 270.xx whql driver to see if that has an impact on gpu usage.

I do apologize if this has been brought up before.