Well as a little test I ran the PPBM4 while GPUZ was open forcing the card to run at full speed - Confirmed in CPUZ

MPE on with GPUZ Open:

21.9, secs Total Benchmark Time
8, secs AVI Encoding Time
7.9, secs MPEG Elapsed Time
6, secs Rendering Time

MPE without

23.1, secs Total Benchmark Time
8.1, secs AVI Encoding Time
8, secs MPEG Elapsed Time
7, secs Rendering Time

So maybe the down clocking of the GPU isnt effecting it and its something else?

GPU Z causes the card to run at full speed. Have CPU and GPU Z open and close GPUZ and watch the rates return to lower clockl?

Makes no difference here.

Makes no difference here.

Mine changes but doesnt seem to make any difference anyways.

Hmm