The RPC1 card is Windows 98se, Windows ME, and Windows 2000 compatable via the latest driver which are on the CDrom, but it is not officially XP compatable yet (beta drivers are available at midiman.com The RBUS card (which will work with all Roland products which have RBUS) is XP compatable, and can use the Midiman Delta drivers for all OS's. Roland will come out with the updated drivers soon.