I've timed my 5D Mk II at 2.1 FPS during burst shooting, which is way lower than 3.9 FPS promised by Canon.
The time of taking a shot does not depend on image quality / size, so I assume memory card is not a limiting factor. I have AF disabled. Tried both with and without live view. Noise reduction is disabled.
What am I missing?
P. S. My speed measurement is very accurate - performed by recording and analyzing shutter sound.