I recently attended a seminar run by canon. (Experience Seminars).
This was for users of the 7d.
The comment was made by the lecturer that there have been reports of the 7D photos being grainy (which I have found).
He commented that that all programs except for DPP stripped out canon specific information - and implied that this was the cause.
I shall have a go myself to see if I can see any difference using the LR converter & DPP (which I never use)