If this is the kind of USB I suggested to Yamaha's engineers who design these things (our PSR Synths), it should take any kind of USB device you want to use. There are USB Smart Media, Floppy Drives, Zip Drives, CD-ROM Burners, etc. If there are any limitations on what USB devices can be used with the 3k, the loss of the antiquated Floppy Drive won't make me sad. It is the first thing to break in most synths. Many Yamaha PSR's won't work unless you can find an exact replacement for the broken FD. Hard to do with older PSRs.

If psr3k works with USB HDD's, that would be my choice. Never again backing up disk by disk but just connect to computer and maby burn all data to cd or just backing up or whatever.