Speed

On a sufficiently powerful PC, UAE will give you quite an authentic flashback into the past.
Thanks to DirectX, the raw drawing throughput of this version will be among the highest of all Intel ports. 800x600 is only about 20% slower than 320x200 on a Pentium 100, although it requires more than seven times as many bytes per second to be pumped across the PCI bus. UAE's native display depth is 16 bpp. This table shows how the net drawing speed is affected by your display type:

16 bpp full screen - 100%
16 bpp desktop - 98%
24 bpp desktop - 72%
32 bpp desktop - 60%

Unfortunately, windowed mode clipping causes system services such as mouse/keyboard input and the file system to slow down (there is no way of avoiding this at the moment). This does not affect SMP machines.
Sound is a luxury. Because sound output is strictly synchronized with video DMA, you won't get clean sound unless your machine is capable of running at 50 fps at least internally.

Rule of thumb: Get a PPro or Pentium II if you want full graphics and full sound at the same time (reportedly, the Pentium MMX 200 MHz, overclocked to 250 MHz, is a powerful platform for running UAE. There are no definite reports about the K6 and the M2 yet, but these should do pretty good as well).

On a Pentium 100 equipped with a Matrox Millennium, UAE-Win32/DirectX is slightly faster than the Linux version under AcceleratedX for programs that perform a lot of screen updates, i.e. action games and demos. All other things should run at roughly the same speed.

Brians personal development system consists of the following:

This system usually obtains Amiga 3000 (68030 at 25MHz) speeds, and gives Picasso96 RTG speeds of at least a PicassoII card.