I know that it's not the same camera but my 7D has the following in the manual:

" The maximum number of frames that can be captured depends on the image size and quality settings".That's in the section dealing with continuous shooting.

All cameras have that sort of limitation - as you would expect because they operate at a finite speed and have a finite buffer. Obviously as technology progresses the limitation gets to be less and less relevant until, eventually, in practical terms it won't be a limitation.

Shooting RAW plus jpeg is the most demanding of the capture modes because it leads to the biggest file sizes and hence the lowest continuous rate. My manual has a little chart that indicates what can be expected. The highest rate is with standard jpeg and small file (as you would expect).

MickLL