I would just add to Casey's explaination that you might want to go to Yamaha's synth site and download the PDF file for the S80 on performances. It can be found here:
http://www.yamahasynth.com/down/s80/s_power.htm
You'll find several PDF's that apply also the CS6x, including how to use the smartmedia cards and the plug in boards (which seems to baffle just about everyone).
Your right about the simillarities between the CS6x and the S80 -- they share the same OS and really the only difference between them (beside the keyboard) are the voice wavs and the dedicated knobs.
hope this helps,
-bruce
[ 01-29-2002: Message edited by: boose44 ]