I saw a notable improvement in certain areas putting dynamic shadows to very high instead of ultra, and for the life of me I can't tell the difference graphically between the two. There was one area where I had an electricity trap set up, and getting close to the trap with shadows on ultra dropped the framerate, but shadows on very high kept it smooth.
Okay... I'll try that first.
EDIT: yep that did it for me.... A door that dropped to 30fps now stays at 58fps with Dynamic Shadows on V-High, and I can't see the difference.... thanks.