Thank you for your information. I also checked out the manual online, and you appear to be correct. I thought there were some background drums in the video I saw, but I did not pay close attention to it, so the drums were probably coming from an external device.
I remember when I bought my PSR-E433, I was also considering a Yamaha MM6 synth, which was being closed out and was available for not that much more than the E433 at the time. It had various drum patterns onboard, but as far as I could tell, if you set up the equivalent of a registration on that keyboard, you would also save the drum pattern with it, and there was no way to "freeze" the drum pattern selected when switching from one registration (or live set, or whatever it was called) to another. That made it a no-go for me. I was just wondering if this new keyboard had something similar, but I guess not.
It still seems like a neat keyboard, with the physical drawbar and synth controls. But while I am looking for a back-up keyboard, this one is still a bit more than what I'd like to spend. Ideally, I'd get another E433 as a back-up, so that I could easily exchange registrations between the one I have now and a back-up with a USB flash drive, but those keyboards have gotten very difficult to find.