Do you mean because of subjective feeling of it independent of speed? Because as for performance, we are talking about emulating a fixed-frequency machine thou

Do you mean because of subjective feeling of it independent of speed? Because as for performance, we are talking about emulating a fixed-frequency machine thousands of times slower. There was no "variable performance", CPU and video timings are pretty much exactly defined. This CP/M emulator was exactly as fast or slow on any stock C64[1], and, correctness assumed, any emulator worth its salt on any non-ancient PC (20 years?) will show no perceptible difference. The "thousands of times slower" is not entirely true, since a C64 emulator has to emulate much more than just its CPU, and the emulator task gets uncontrollably preempted. But there is no way that CP/M will feel any different on the real machine, in terms of performance. [1] The only significant exception was that NTSC machines were a tiny bit faster than PAL machines: A tad over 1MHz vs. a tad below 1MHz, to fit the respective video standard's timings.