Hi
I'm finding that too with the 8.1 windows version even though 'gen=0' is in the .conf file. This causes the miners to lose half their hashpower.
My only solution so far is to set Bitcoin-qt's cpu affinity to 1 or 2 cores.
The previous versions and other crypto clients do not have this problem....
doesnt the command gen refer to the client trying to mine for coins? I haven't told it to mine for anthing as of yet. i set its affinity to 1 core, cpu hovering at 60C, and it still hasnt synchronized.... thanks though!