you have to change settings in tracker. setup>configure>use specified numbers of CPU cores>type 7 cores to use.
Apply>stop all clients>start all clients.
had the same problem.when also using cpu and gpu,the gpu have to use 1 core.After this it should be 24/7 folding.
PPD it depends ,which WU you are folding,WU 2684 can take 72hours and as low as 20.000ppd.
right now im folding 45.000ppd at WU2686 on the cpu(
i7-950@4.2ghz) and WU6806 on my gtx460(900@1800@1030).
cpu=32500ppd.gpu=12500ppd
Hope this will be any help.
Happy folding
ive tried this n so far so good now running smp and gpu3 on both cards @ 65k ppd happy folding

thanks to kilobravo