Turning off motion blur on my computer dropped batch count by a factor of 3 to 6 and increased the FPS by a lot. I tried turning it on and off with the demo paused. One time I was around 23k batches with motion blur off and 120k with motion blur on. this is while paused so the numbers didn't change as I flicked between motion blur on and off.
With high batch count my CPU usage for this demo was around 24%, and GPU usage around 20%. With low batch count my CPU usage was around 70%, and GPU usage 99%.
can you post that configuration?