Can V6 use the GPU even if V6 is idle?

My laptop fans starts whirring almost as soon as I start the WIP, it seems like it is calculating every frame even if the model is unchanged as the GPU sensors quickly reaches 65 deg.

Macbook pro with bootcamp and Windows7, GeForce 330M

Some more information, running R6 on Windows 8.1 on a bootcamped iMac. When rendering the fans start working hard but they cut out again as soon as I stop. Processor usage is flat across all 8 cores when Rhino (and everything else) is idle.