HDR on 5dmk2

[palbanet]

Hi all,
I've installed the brand new 2.3rc2 on my 5dmk2 and I begin the HDR test.
Actually I have due some test and it seems that is very unstable.
It's 1 low 1 high at the beginning but it loss many frames during the shot.
So what next? Could be a card problem? A faster card can solve the problem?
Whis is a good card for this work?
Many thanks in advance, best regards
Paul

[a1ex]

Could not reproduce (5D2, 500MB video, 25p, 266x card) - not even one missing frame.