I believe that Memory Stick is Sony's non-compatible proprietary over-priced regular flash memory, whereas Magic Gate is Sony's non-compatible proprietary over-priced flash memory that additionally supports ATRAC3 and copy protection. I think you can use the regular Memory Sticks in both your devices without problems, presumably you want to transfer JPEG photos to display ? You can't play a Magic-Gate-with-protected-content back in your Memory-stick-only slot, but you can play a Magic-Gate-without-protected-content in it.

Regards

Mark