As I understand it, a multicore processor won't split a single thread across CPUs, and Csound is definitely single-threaded. However, the OS itself should be able to take advantage, running sound output for instance on a separate core.

I've been running Csound on a dual-CPU BeOS machine for a few years, and I find that, for something like my Hammond emulator which makes fairly heavy demands (on an old, slow box!), I can't turn off one of the CPUs without completely wrecking real-time play. (Less demanding configurations still run fine without both CPUs active.)

So I'd expect a multicore machine to certainly be an advantage, even if Csound itself can't use it.

Well, it might be more limited but i suppose i could run 2 instances of csound. Both running the same files but receiving midi from a different input. I could then take advantage of my dual core.

Anyways, for now it's working pretty well on a single core :)