A friend of mine just got an R4 DS and a 2gig Trancender (I think that's the name....) Micro SD. There was a bit of an issue with formating the card in the beginning but as far as actual use it was the same (so far, I only started a couple of games to make sure that it was working ok), so until he complains I'll say it works the same as a 1 gig. I only have a 1 gig card bcs it's cheaper to buy two 1gig cards right now than one 2 gig card at a lot of places.