A not-dissimilar situation has shown up in a couple different places, related to the nVidia M series video adapters. Apparently they have a mechanism whereby they flip in and out of high-performance mode depending on what's being demanded by currently
running software. The problem is that in certain situations this switch can happen several times within a few milliseconds and create problems for Windows. (I've only seen this come up in relation to 64-bit versions.) The fix, copied from an OCZ forum, came
courtesy of Winston Smith:
Update Driver
- Download and install the latest NVIDIA driver from here .
RivaTuner
- Download and install RivaTuner from here .
Magic
- Open RivaTuner and switch to the "Power User" tab.
- Expand the "RivaTuner\NVIDIA\Overclocking" Tree.
- Set "EnablePerfLevelForcing" to 1.
- Switch to the "Main" tab.
- Under "Driver settings" click on the small arrow left to "Customize..." and choose the first icon "System settings".
- Set "Force constant performance level" to either "low power 3D" (suffient for 2D audio work) or "performance 3D" (used for 3D gaming).
- Click OK and let the computer restart.
I would start with step 1, update the driver, then if the problem persists download RivaTuner and continue from there.
This even handles a problem of Windows 7 x64 (or Vista x64) freezing completely under certain circumstances on the MacBook.