Emulator speed decreases with higher screen depths, though only little difference between 8 bit and 16 bit mode.
These timings were taken at one single Mac, with two video cards attached. Emulation using the VRAM card is twice as fast as using the NUBUS card in all screen modes. This means, video memory acces to the NUBUS card must be slower by factor ~ 4. Video memory access to this card is especially slow, i had an old NUBUS card which was faster (somewhere between this NUBUS card and the VRAM video).
Z80 Engines
The 68020 versionincludes three z80 engines, which are different in speed and accuracy.
All measurements with 256 colors and refresh rate 1:5
68020 version 'fastest emulation' Performa 630 260%
68020 version 'better emulation' Performa 630 233%
68020 version 'best emulation' Performa 630 ?
68020 version 'fastest emulation' PowerPC 6100/60 82%
68020 version 'better emulation' PowerPC 6100/60 66%
68020 version 'best emulation' PowerPC 6100/60 16%
PowerPC version 'best emulation' PowerPC 6100/60 278%