Just wait for a while since no gc emulator yet has decent speed.Can't tell you system requirements but when it does become playable expect to have a decent pc at least athlonxp or pentium4 midrange types.
for now, id suggest patience
i havent seen org for months now i should check with Knuckles if he's seen him...
the latest news were that org was completly rewriting the core, which was still incomplete the last time i spoke with him. (CVS hasnt been updated also)
compatibility should be better in next release