Run a task and time it (don't simply rely on !Sick to give a report).
Tasks that are *not* good ones are disk access based ones as the emulator uses windows native system (and UDMA to access it). A real RiscPC (unlike Iyonix) lacks UDMA so the test would NOT be a fair one.
Screen update tasks like full screen scrolling a large number of numbers - recording the time taken for the *exact* same BASIC V program at exactly the *same* resolution and colour depth on a real SA-RPC and an emulated one.
You could also try arithmetic operations on both (this stuff is all just off the top of my head so add your own).