I decided to do a test to see how many frames it would take to fill the buffer of the camera in various recording modes.
Camera used 60D, 1000th of second shutter speed, manual focus, high shutter rate (5.9 frames per second)... The list is of how many shots it took before the buffer filled and the frame rate dropped.
RAW and Ljpeg (5184x3456) - 6 frames
Ljpeg (5184x3456) - 8 frames
Mjpeg (3456x2304) - 8 frames
S2jpeg (1920x1080) - 8 frames
RAW (5184x3456) - 14-15 frames
MRAW( 3888x2592) - 15 frames
SRAW(2592x1758) - 15-16 frames
Before the test, my assumption was that smaller files would mean more files dumped to the memory card before it stuttered, and that small jpegs should allow a much larger number than full sized RAW files. In fact, the opposite happened.
I interpet the results to mean that my assumption of writting the files to the flash drive being the bottleneck was wrong. It seems obvious that the internal memory becomes filled with RAW data waiting to be converted to Jpeg... the bottleneck is processing to Jpeg.... get rid of that process and the number of pictures before stuttering doubles. The next bottleneck is processing the raw files (including reading them off of the sensor), changing the output RAW size has almost no effect on the buffer, so once again, the flash card is not the bottleneck.
So the limitation is computing power.... not card speed. Anyone care to try this test on a different camera model?