A month or two ago I mentioned I was working on an emulator benchmark within RetroCopy but I never released it publicly. I spent a few hours tonight putting something together for 0.400B
It helps to determine what works when optimizing having a decent benchmark. I do need to do some further work on optimization at some point, but the current emulators are fast enough for the minimum spec PCs I'm targeting so I'm not too concerned about it yet.
The benchmark runs a "fully loaded" Master System as fast as it can go. This is emulating the PSG, VDP, Z80 and FM chip for a total of 21 million cycles per second. Since RetroCopy is cycle accurate it actually goes over every cycle compared to most other emulators which do their work in much bigger chunks. A good standard emulator running the combo described would only be emulating about 2-4 million chunks per second, so RetroCopy is up to 5 times more accurate than typical SMS emulators. It is also of course maybe 5 times slower than those emulators. 