OK I gotta disagree here, If you make your game run in 0.5Mb on an A500, it will work the same speed on all A500 because it won't make use of the Fast RAM and it won't make use of any FPU unless you code it to, that's what I was talking about. Also the chipsets on the A500/A500+/A600 really didn't speed any games up that were written for the lowest common denominator, i.e. the A500. Besides if timed to vertical refresh, it was EXACTLY the same on all 3. Perhaps if you made a game for an A600 that used 99.9% of the time available between v-refresh, and then ran it on an original A500 it might take 100.1% and thus drop the odd frame but I doubt it. It was totally possible to make a game run the same speed on all Amigas. Of course it was possible to make some games that ran faster depending on the chipsets/RAM/FPUs etc like those crappy 3D Doom clones that came out at the end. I only say crappy as you never had a hope in hell of getting them to play smootly on anything less than a beefed up A4000 or similar.
The presence of a memory upgrade made a huge difference to an Amiga's performance, it added nearly 50% again to the raw speed
I had a memory upgrade and guess what, all my games ran at the same speed i.e. 50Hz. Also when I got an A1200 and got the A500 games working through various ROM Disks, they ran at the same speed too. Internally the hardware may have competed it's operations quicker but as it was timed to vwait, this was irrelevant. That's the whole point I was making.