i can''t figure out why mipmapping is so popular. it''s slower than linear filtering, and wastes much more memory. and i don''t see any difference in appearence, at least not my machine.
what are the benefits then?
Free your mind.
As textures minify (word?) the pixels are of course not all able to draw. If you move the camera/object just slightly, it can affect SOME of the pixels drawn. This gives horrible sparkling effects. Also, the visual clarity of a mipmap is generally more visually accurate than linear filtering. Anisotropic filtering (or trilinear mipmapping) gives me by FAR quality rendering of distant planes. These effects are most noticeable when the distant plane's normal is almost perpendicular to the viewing angle (such as far away floors). 3Digest has nice page which details this.
mipmapping will improve performance on all cards the reason being when a texture is a little ways away GL_LINEAR_MIPMAP_NEAREST will use a say 4x4 sized texture but GL_LINEAR will have to use the original sized texture say 256x256. but thats not the main benifit from mipmapping its main benefit is its gets rid of most of the aliasing problems.