Minimum Graphic Card Requirements
Here is a rundown on the various Unity features supported by different generations of video cards.
(This is a WIP and is very incomplete and messy, based on my very preliminary and sketchy research. Please contribute by clarifying, correcting, adding items or cards, and formatting. Thanks! Steve)
OpenGL Capability Resources
Application to test OpenGL compatibility of your graphic card Also includes database of large number of cards and platforms so you can check cards you don't have. Works on both Windows and Mac
Integrated Intel graphics
Pixel shading 1.0 & 2.0 supported by 82915G/82910GL and above
Vertex shading 2.0 in software for DirectX supported by 900/950.
(Does that mean it's driver dependent or game code dependent? How is Unity doing on this front?)
Render to texture
Render to texture support (GeForce2 or Radeon 7000) Also can use PBuf (Current problems with Intel under investigation.)
Vertex shading GeForce 3/4 or Radeon 8000 Also works on Intel 915 under XP
(Note: As of 11/22/06, this is the preview version, which has no fallback. Shipping Nature Renderer version will fall back to a less demanding version and have overall higher performance.)
OpenGL Pixel Shaders 1.0 (GeForce FX 5200 or Radeon 8500)
(Will be fairly widely visible by decent non-Intel cards. Should fall back to flat color.)
Noise, Color correction, Edge detection, Sepia, Grayscale, Twirl, Vortex, Refractive water
OpenGL Pixel Shaders 2.0 (GeForce FX 5200 or Radeon 9500 or higher)
(More demanding. Don't assume users, especially with Intel cards, can see it.)
Refractive water shader fallback doesn't seem to be working on some cards (Intel?) as of 11/21/06.