Hi Gibson,
There are no newbie questions.

When you play in auto accompaniment mode each note of the accompaniment takes up from the polyphony no matter how many keys you have pressed with your left hand.

When you play in full keyboard more each note of the drums track eats up the polyphony.

Basically, every sound that comes out of your keyboard uses polyphony.

Squeak and Rick, Yesterday I went over the local yamaha store and noticed they have the YPG-625. Tomorrow I'll try it and will post my review.

Regards,
George