Why don't you want to put the O/S on the SATA drive along with your data? I don't quite understand this one. Anyway, if you're running windows 98 or ME (i think me does it) you can tell windows to use a different drive for Swap file space. I think that's about all you can do. Now if you are running linux, that's a different story. If you're running XP, I don't think anything good will come from a flash card.