I found a strange phenomenon of my GPU, follow list are what i do:

1. open my video game window normally

2. look at the core clock and load of my gpu with GPU-Z, it's 810MHz and 60% load, nothing unnormal

3. minimize the video game window for a long times(>0.5 hour)

4. look at the core clock and load of my gpu with GPU-Z, it's 60MHz and 100% load, it's uncommon

5. restore my video game window, because of the unusual state of gpu, my fps is so low, about 2 to 5

6. the gpu can't restore normal state until i close the game window and run again

my machine:

OS: windows XP sp3

CPU: intel i5

GPU: Nivida GT630

GPU Driver: 301.68

DXSDK version: August 2008

i don't know why? who reduce the core clock of my gpu, the driver or d3d runtime? any idea about this? thanks!

sorry for my poor english

It's a power-saving feature of the driver. D3D doesn't do any power saving. The problem is that the core speed doesn't come back up, so it's a driver bug.

I had a similar problem once: whenever I'd wake the PC from sleep, the GPU core speed was stuck at the speed it was when I put it to sleep. Maybe you're haveing the same problem - then it has nothing to do with the fact that you minimize your window, nor with D3D.

It's a power-saving feature of the driver. D3D doesn't do any power saving. The problem is that the core speed doesn't come back up, so it's a driver bug.

I had a similar problem once: whenever I'd wake the PC from sleep, the GPU core speed was stuck at the speed it was when I put it to sleep. Maybe you're haveing the same problem - then it has nothing to do with the fact that you minimize your window, nor with D3D.

it seems that the only way i can do some things for this is to update my driver!

i will try! thanks for your attention!

Yup. Driver bug.

You said you minimize for a long time. If the system entered in suspension state in the meanwhile, it's quite likely the driver and/or the program will have a problem to restore to normal operation. You're using Windows XP which did an "ok job" with that.

Launching another GPU demanding game can trick the driver into restoring its GPU state.

Another thing to consider, if this is a laptop, the driver may be downclocking the GPU not because it goes idle, but because it is overheating. Hence it won't go up when you restore the window because it's still hot.

got it! thanks a lot!