Often, after I've had the computer unplugged to work on its insides or after recovering from some sort of crash, when I go to start up GPUGrid WUs, my GPU will swing wildly from max clock speed to min clock speed resulting in very slow processing.

I've found that I can fix this by switching my GPUs over to another project such as Prime Grid temporarily and when I come back (after perhaps 20 minutes/2 WUs) the clocks will stabilize at max speed for GPUGrid.

I'm just curious if anyone else has ever seen this and what may be the cause of it. I'm running 2 GTX680s and usually it's just one of the cards that will do this.

The last time this happened (yesterday) I believe I was running SANTIs, but the type of WU doesn't seem to matter. I can usually predict with almost perfect accuracy that under the conditions I've described that I'll see this issue after resuming work regardless of the WU type (though I only run Long tasks).

I never seem to have a problem when I suspend crunching or close out of BOINC altogether and then start it up again. A normal shutdown or reboot won't have any effect either. I have Nvidia set up for maximum performance.

I don't know why switching to another project fixes it. Almost seems like the system has "forgotten" what it's supposed to do and running something else for a few minutes reminds it and fixes the problem for GPUGrid.