Isn't my card supposed to downclock between games?

I have an M1530 with the 8600M GT, and using rivatuner I've overclocked my card many times. Currently I have the 179.14 drivers, and I was using rivatuner's monitoring graph to follow the temperatures and the clock speeds of the card. Before a game starts, the clock speeds were chugging along at the normal idle frequency of 275/301 or something like that, and then when the game began the speeds jumped to what I'd set the performance 3D overclock to, something like 550/850. However, once I left the game the clock speeds remained the same rather than downclocking back to the low-power level... I'm pretty sure I used to notice my card downclocking after leaving games, did I screw something up or how can I correct this?

 

Use the official 186.81 drivers from NVDIA website... they should have no powermizer or heat problems..

 

I've found the problem to be driver dependent. However, if you're particularly attached to your current drivers you can just set an 'idle' clockspeed (same procedure as overclocking) and use that setting when not gaming.

 

Latest drivers have powermizer in, automatically cut my clocks down a lot when idling.