Nope - 6.0 fps with and without the grip... some grip review notes too...
I received my grip about a week back and just yesterday did a test to see if there was any fps boost when shooting with the grip vs without...
5D Mark III, genuine canon LP-E6 batteries, fully charged. Canon BG-E11 grip.
I recorded the sound of the shooting, pulled the audio over to my PC, looked at the wave form in a sound editor and lo and behold - the same frame rate both gripped and without grip.
All that said - I will report that the new grip is great. When mounted, the 5D3 is taller than my 1D4. The "portrait" section of the grip feels larger (I've not actually measured it) than the portrait section of the 1D4 too.
Nice to have the second joystick, but the positioning is a touch different than on the main grip. To put the second joystick in the same relative position, it would need to be about at the location of the large wheel "lock" switch. So they had to move inboard a bit to keep it actually on the grip. I'm still reflexively reaching my thumb over to the "main" joystick, but slowly re-training myself...
The construction is super solid feeling, I like the new door setup that mimics the 1D series battery insertion/sealing.
I'll be doing a post about the grip soon - along with the huge advantage of using udma 7 cards in both the 5D3 and the 1D4...
Let me know if there are other questions about the grip...
- Will