Hi
I've just built a 1 hour Blu-ray with 2 motion menus containing 12 buttons on each.
Although Encore didn't look like it was doing anything, it took 3 days to render this.
I kept an eye on the system manager in Windows which showed that Encore was always using a minimum 19% of system resources, so it hadn't crashed. (I also clicked on the main Encore window header and got an audible warning, so I left it to build everything over the weekend.
Once the Chapter menus were built, I changed a number of button links and it rendered really fast, although I suspect moving a chapter point would take as long to render again. Not much fun!
I presume it's because it'e re-sizing HD footage down to a postage stamp.
Cheers
Martin