Yeah, my comp is a real beast. It can run the Twilight Princess for the GC intro full speed (I didn't begin playing yet).
I've yet to try if I can read my GC games with it (I mean the boot from disc option or even better, dump the games).
I run this stuff in Linux by the way. I just switched to AMD's proprietary drivers so that I can exploit my GPU and run native Linux games without needing Windows (which I only use for Windows games anyway).
Edit : I can't read GC disc in my DVD drive. That was to be expected.
Edit 2 : I'm in the process of configuring it to use my DualShock 3 (it'd be better if I could plug a GC controller, but I need an adapter, and the DualShock feels better anyway).