Bernd Schmidt

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Bernd Schmidt is the original author and maintainer of UAE

In 1997, when computers were much slower than they are now, Bernd Schmidt, chief designer and author of the UAE emulator, described some performance issues of the custom chips as follows:

All timings I give here were measured on my machine, a 90 MHz Pentium, using SVGAlib, with the FASTER_CPU and DONT_WANT_SOUND options... For games and demos, the CPU speed does not matter, but the average frame time is important... A real A500 has a constant frame time of 20 ms (50 Hz). If you have a game/demo that has lots of blitter activity, many copper/sprite effects, dual playfields and scrolling, no one can help you. Fortunately, this case is extremely rare. Normal games that have a number of blitter objects, scrolling and maybe some sprites run at 1/3-1/4 the speed of an A500 in the worst case, some run at 1/2 the speed. Lowering the frame rate helps enormously here, and at 1/5 frame rate, about everything runs somewhere between 50% and 100% the speed of an A500. This still isn't the full story (I bet you start to see why the question is hard to answer). A real A500 without fast memory gets slowed down to about half its speed in Hires 16 color mode. More bitplanes also slow UAE down, but not quite as much, so it can be several times faster than an A500 in that mode.