I have a demo, that shows an image under non-compressed, DXT1, DXT3, and DXT5
download it from
Its the 2nd one down. If someone has an ATI card, and could screenshot it in non-compressed, and DXT modes, that would be cool.
requires DevIL image library too;
BTW, you press space bar to cycles modes, on my Gf3 at work, I can easily see a degradation from non-compressed to dxt.