Are you using vmware to fold on the cpu? If so I get similar results. Check out this thread:
Boost Your PPD with VMWare - Look inside for easy guides!
If you are not using vmware for the cpu, set the cpu priority in the advanced options to slightly lower, and make sure the gpu clients are set to slightly higher.
Even if you are not using vmware, you might want to, and check for priority issues and discussion there for more ideas.
If you want something else quick thing to try, use ctrl-alt-del, and set all the processes for the GPU in task manager (will read fah_core 11, or core 14) to "below normal". This is higher than the default.