I do some action shooting but not often. I am glad to know that you are able to use the 600x cards in burst mode without a problem. As I mentioned the camera package includes a 32 GB Sandisk 400x card that I can use for regular, non burst, shooting. I just don't know whether the relatively faster write speed of the 1000x is of any practical advantage over the 800x. The only reason I have to buy a faster card is for action shooting. I don't plan to do video.