I have found the following with GPU-Z on Nvidia GTX 460M . 1. Here are basic lPC specs : 2. I find with about Ver. Nvidia 285.62 and later , when I start playing a movie , the GPU load is about 20% as normal . After a few seconds , it will go up to around 70% and stay there , and GPU clock will adjust down to 202.5 and VDDC to 0.8120 V : These adjustments occurr , even if I am not playing any video , just running GPU-Z : 3. With Ver. Nvidia 280.26 , GPU load is about 20 % and stays there , as do GPU clock and VDDC : 4. Might it be that GPU-Z is not measuring correctly with newer drivers , or that it's presence is somehow causing these parameters to adjust ?