Thanks for the reply. No, that's not it. Affinity is already set to different cores in the mining software (GUIMiner v2011-07-01).
I just find it strange that I haven't read about anyone else having a similar problem. Is my setup really that obscure? Win XP 32bit,
more than one video card. When I first started out a few months ago I was using 11.5. Everything was working fine but I read
that performance could improve with the 2.1 SDK so I switched to that from the 2.4 that came with 11.5 and it worked, performance
did improve. When 11.6 came out, I upgraded to it. It didn't make any noticeable difference, but didn't screw anything up either,
so I just left it. Now that 11.7 and 11.8 are out, trying to upgrade to either one screws things up so I can only effectively use one
video card. I've tried uninstalling the old drivers and using driver sweeper to clean them out before doing a clean install, it didn't
help. I've also tried both installing 11.7 or 11.8 seperately with SDK 2.1 and together with 2.5 that comes with it. Nothing I've
tried works. I'm sure hoping someone sees this that has some ideas for me to try.