DavidB: The Intel Macs have multiple CPUs, called "cores." Mine displays 4 little bars when you run Activity Monitor.
Right after opening Alice, before doing anything at all, Activity Monitor reports that Alice is using "93% of CPU." Two of those four bars are about halfway up. The CPU gets hot; the cooling fan comes on. Alice is doing a whole lot of thinking about ... what?

Debussybunny: Actually Alice is not using all that much memory, 126MB out of 4GB. Alice is just... thinking about something.

DavidB: Not just my computer. I installed it on another Mac, same behavior.