i'm not so sure about it guys a friend of mine, got a 128MB card in his 303 and it works but sometimes his, sample's are messed up and thats not happend with a 64MB card.

I have had an issue with the 303 on the c/d banks. It would sometimes erase samples randomly on the card banks. Thats why i bought a 404. Sorry, I dont know if it is a card issue but that has happened in the past on my 303. This is with the 128 Jamedia card.

hmm, well i posted in this thread a few days ago saying my 128 mb worked fine, but just yesterday my sample pad#1 on bank d was mysteriously deleted...hopefully i accidently deleted it somehow rather than it being a problem with the card, but you guys are now mentioning the problem of missing samples..........hmmmmm

UPDATE:

I think the 128mb card is not compatible. While resampling a sample to another pad, the new sample had a loud click/buzz at the end of the sample. I marked it so it would cut out the part with the click, and then I tried to truncate.
My sp froze during the truncate process. I had to reboot, and now all the samples have period click/buzz sounding throughout sample playback.

And this is only happening on the card memory.