Well, you should be getting more than that, I'd say...

I have a 6950 that can get 15-20k/day by itself. Yesterday was 34k, which was a bit of an anomaly. But you do have to run it for quite a while for pendings to catch up to the new tasks you're completing. I'm running 4 WUs at a time on that card, reserving only 1 thread for those four WUs.

I've also run SETI on NVidia cards. I've found that you have to reserve an entire thread per WU, which was just a bit unacceptable for me, so I stopped doing that. And the NVidia cards didn't seem to do as well as the AMD cards.

And I've been running stock apps. No optimization.