To speed up the emulator you need to disable things like Rewind, that take some of the powers. I managed to get full speed for snes. I don't know about additional chips, probably it does support them.
It took years because rerecording emulators were developed slowly, by few people, and independently from each other. BizHawk unites the comunity's powers, as well as platforms, to emulate as much as possible as well as possible. And it's currently VERY actively developed, features are implemented in days after you request them, so join in and request some.