What's the title of the demo?
Sonar_AudioDemo loads/plays fine here, barely registering at around 10-15% cpu.
The Jodi Good track takes more juice, around 15-35% cpu, but also plays fine.
Note that I'm on a five-year-old Q6600 (slightly overclocked) system, so if you have anything newer/ faster (and it's not 32bit) then something is likely wrong with your setup.