This is only an approximate guide - I can't be exact because every PC is different! I am going to give you the requirements to run games at real speed - it will work on slower PCs but you won't enjoy the experience ;)

CPU
Nemu has exceptionally high CPU floating point performance requirements. Realistically you will need at least a P3 or Athlon 600Mhz to get 30 frames per second in a relatively simple game such as Mario64. I recommend 700Mhz or above. That will give you a fairly solid 30fps in most games. However, there are still many games that would need roughly a 1.5 Ghz (!) P3 to run at full speed, even though, at the time of writing, no such chip exists.

Video (graphics) cards
Nemu requires Direct3D hardware acceleration, to achieve playable framerates, and that must be on your primary (not add-in) card.

Recommended video cards
The ideal card is an nVidia TNT2 or GeForce, simply because this is what the video plugin of 0.7a was written for.

Alternative video cards
Nemu also works well, albeit with more glitches, on any other recent (roughly 1999 or newer) Direct3D graphics card, such as the Matrox G400 and the 3dfx Voodoo3.

Nemu and 3dfx graphics cards
Nemu has some problems with older 3dfx cards, which is unfortunate, to put it mildly, since so many of us have them. Please understand that any card since the Voodoo3 can work with Nemu!

• Voodoo4/5
  The recent 3dfx cards should work fine, just keep your drivers up to date.

• Voodoo3/Velocity100
  Download the latest drivers from 3dfx and set your desktop colour depth to 16-bit (16-bit, not 16 colours!). Now you should be able to run Nemu fullscreen and in a window. I have tested this myself, it does work! Expect some extra graphics glitches compared to a TNT.

• Voodoo Banshee
  Should also work if you set your dekstop colour depth to 16-bit and are running the latest drivers. Expect more glitches than other cards.

• Voodoo2
  Tricky. The problem here is that this is a secondary video card, and nemu requires acceleration on the primary card. As a workaround, you may be able use a utility called Powerstrip to swap your Voodoo2 over to primary, making it available to Nemu. Unfortunately I can't tested this myself, as I no longer own a Voodoo2, but I have reports that it works. Other things to try are setting your desktop to 640x480 16-bit colour and setting Nemu's resolution to match that.

• Voodoo Rush
  I think it just ain't gonna happen. Upgrade!

• Voodoo1
  Nope. It's very unlikely that this will ever work properly. Upgrade!

Sound cards
The current version of Nemu uses unusual sample rates, and does not use DirectSound. The result is that sound apparently only works properly on the creative SBLive!. The next version of nemu will support DirectSound and thus all DirectSound compatible cards (which means pretty much all sound cards!) should work.

Keyboard & Gamepads
Nemu supports keyboard and joystick input simultanesously via DirectInput. Thus you must have a gamepad properly installed in windows (Control Panel > Game Controllers) with the buttons mapped as directx buttons, in order to be able to set them in Nemu. Nemu also supports all Axes available on your stick/pad. (x,y,z, etc.) Nemu supports the Adaptoid for connection to a real N64 controller, with Rumble effects.