Here is my Startis Benchmark FRAPS test on a:
i7-3770k at 4.1GHz
GTX 970 Gigabyte Windforce OC G1
GTX 670 Ti Gigabyte Windforce OC
*GTX970 weas the GPU for all tests
Processor controlling PhysX processing
Values 670 970 CPU Auto
Average of FPS 57.6 59.6 58.0 59.1
Min of FPS 21 21 20 22
Max of FPS 83 86 79 75
StdDev of FPS 9.8 8.8 7.8 8.0
The dedicated GTX670 (w/ 970 as GPU) has problems at the beginning, even though the averages are not much different..
Auto CPU GTX 670 GTX970
Average of FrameTime 16.90 17.25 17.36 16.77
Min of FrameTime 0.38 0.41 0.37 0.42
Max of FrameTime 172.27 184.01 177.79 174.34
StdDev of FrameTime 5.27 5.44 5.61 5.40