Compatibility is the percentage of software output perceptibly reproduced by emulation. Accuracy is the percentage of hardware processes faithfully reproduced by emulation.
I personally had never heard of this emulator before, but I am going to try it now. They recommend a Phenom II or Core 2 Duo as minimum to get acceptable performance, which is reasonable for near-full compatibility with games, IMO.
Top Ten Things Overheard At The ANSI C Draft Committee Meetings: (5) All right, who's the wiseguy who stuck this trigraph stuff in here?