Wed 05-Sep-12 12:44 AM | edited Wed 05-Sep-12 12:45 AM by RockyIII
You do not need to use two cards unless you want to. You can leave slot 2 empty or use a card in it for overflow or backup (either RAW or JPG). You can also use slot 1 for stills and slot 2 for videos.
I also use SanDisk Extreme Pro cards. Here is some test data comparing the speeds of various cards: