Here are my results when I removed my OC. Cliff notes: I got a huge performance hit.
Intel i5 3570K, @3.8 GHz, 16 GB RAM 1600 MHz CL 11-11-11-30, SLI 2x GTX 770 2GB, Windows 7 Home 64bit, Resolution 1920x1080
maximum quality:
min FPS: 6
avg FPS: 35.7
max FPS: 45
quality:
min FPS: 7
avg FPS: 42.6
max FPS: 59
performance:
min FPS: 47
avg FPS: 58.1
max FPS: 71
JON-PCnoOC.txt
All in all, I reduced my turbo speeds from 4.4GHz to 3.8GHz, which is about 13% less. My average framerate suffered by 13-16%, which is pretty consistent for performance scaling.
maximum quality:
3570K @ 3.8GHz avg 35.7
3570K @ 4.4GHz avg 40.6 = 14% higher
quality:
3570K @ 3.8GHz avg 42.6
3570K @ 4.4GHz avg 49.4 = 16% higher
performance:
3570K @ 3.8GHz avg 58.1
3570K @ 4.4GHz avg 66.0 = 13% higher