All my GPU's are now running 9401 WU's instead of 8900 WU's. Are you on the same boat? The WU's gives more credits but take longer than the 8900 and at the end even on my 780's the overall PPD is below what I could achieve on 8900 WU's.
Here's a very quick look from this morning.
Both my 670 FTW saw a decrease of around 8000 PPD
One of my 770 saw a small decrease of around 2000 PPD but the other one is increasing over 15K PPD?!?
One of my 780 is still around the same PPD but the other one is increasing over 50K PPD?!?