to se how good is your CF card simply make a test in ML menu...
my kpb 64mb have avg speed about 92mbps
WHAT IS IMMPORTANT is -----> Write speed (Buffer= 16384 K) if you look my picture.
https://www.dropbox.com/s/lp0w5qvn0pfmxp2/VRAM4.BMP
in my picture you will see the Write speed is (Buffer= 16384 K)---> 94.6MB/s
so that is the speed of card - the tasks what your 5d3 needs to run to make movie and what data rate can get out for raw recording.
my kpb 64mb have avg speed about 92mbps
WHAT IS IMMPORTANT is -----> Write speed (Buffer= 16384 K) if you look my picture.
https://www.dropbox.com/s/lp0w5qvn0pfmxp2/VRAM4.BMP
in my picture you will see the Write speed is (Buffer= 16384 K)---> 94.6MB/s
so that is the speed of card - the tasks what your 5d3 needs to run to make movie and what data rate can get out for raw recording.