but you don't see it with the vast majority of amiga software.
You'll see the speed everywhere, even in Workbench popping windows and icons up. Obviously most games are supposed to run at a certain speed, so of course further acceleration isn't going to do much for them.
btw I have had amigas with 68000, 68020, 68030 25mhz and 50mhz, and 68040
Not too bad, I've had 68000, 68010, 68020, 68030@25mhz, 33mhz, 40mhz and 50mhz, 68040@25mhz, 33mhz and 40mhz, and 68060@50mhz.