Idle state during gaming??

I'm getting this weird issue when I play games... my normal clocks are 765/1125, which changes to 400/1125 during idle state...

Whilst playing games this might randomly change from it's active 765/1125 to a weird idle state of 400/900. Never happened before now.. The new drivers maybe? I can still play games.. But I see like a 50% reduction in FPS and a loss of smoothness. I.e. L4D2 is usually 100-150 fps max settings (full aa), etc. But whenever this happens I drop to about 70 and have random little stutters here and there.. Playable, but annoying. It drops the voltage to 1.0 vs 1.0875 for its active too. Anyone else had this?

Most new cards seem to be doing this to me. My 260, 460 and friends 5850 and 6850 also do it.
There is a way to prevent the underclocking feature, hopefully someone can tell you how, subscribed to the thread because I'm interested as well Sorry I couldn't be more help.

Back in the good old days (8800TX, HD 2900 and earlier cards) the power management of GPUs was very simple. Running normal desktop apps put the GPU in the 2D power state. Running a 3D app in a window put it in low power 3D state. This is why running games in windows had such a big effect on performance. Running a 3D app in exclusive mode put it in full power 3D state.

Nowadays GPUs are much smarter than that. Now the switch performance state based of GPU load. So if you are in a game and get dropped to a lower performance state, this is likely because there isn't enough for the GPU to do. Could either be a sign of a bottleneck somewhere else in the system or just that the game caps the frame rate in order to not unnecessarily heat up the GPU.

It does get more complicated that this because exactly what the clocks are in these different states depend on what mode the GPU is in. If you are using the GPU for video decoding the clocks in these states are different than they would otherwise be.

None of this completely rules out a driver bug since it has a role to play in all this power management.