The TNT2
TNT2 Lowdown
The TNT2, and the faster version, the TNT2 Ultra, come in way too many flavors to bother describing here. Almost every single video card manufacturer has a different TNT2 configuration, from clock and memoryspeeds to feature availability (the card with the most features has to be the ASUS, though it is a slow card by TNT2 standards.)
A standard, "vanilla," TNT2 runs with a 125MHz core speed and a 150MHz memory speed, though many manufacturers go a little bit faster than this. A TNT2 Ultra runs at 150MHz core speed and an 183MHz memory clock. Again, many manufacturers set these a little faster. At one time NVIDIA planned for the TNT2 and TNT2 Ultra to use the 150/175MHz and 175/200MHz settings respectively, but lower than expected yields forced nVidia to drop recommendations slightly. Until recently, Hercules offered 175/200MHz TNT2 Ultra boards, but since they went under, I think the fastest TNT2U out there is the Guillemot Maxi Gamer Xentor 32 Ultra, at 175/183MHz (Please don't write in telling us about the Falcon Northwest TNT2U board, unless you actually own one. As far as we know, the project is kaput. -ed.). They are relative newcomers to the North American market, but are considered big players abroad.
Memory
TNT2s can have 16 or 32MB of memory - most I know of offer 32MB, since that is likely to sell more and for more. However, with the recent jumps in memory prices we might see the 16MB flavor becoming more popular. Still, the 32MB of available memory makes the TNT2 a better long-term investment than the V3 simply because it won't be as limited by future game designs using large textures. You might also want to note that TNT2 cards offer 32bit color (which doesn't make much of a difference in today's games, though in the future it will), and support texture sizes up to 2048x2048 (it's almost standard in current video cards.).
Overall, general consensus puts the TNT2's image quality just behind that of the Matrox G400 series. The TNT2's 2D image quality is again excellent, though still not quite the insane standard of the Matrox cards, it is as good as Voodoo3 (At least, I can't tell the difference.).
Performance of the TNT2s is usually on par with Voodoo3s, except in games with Glide support, then the Voodoo3 takes a significant lead. Also, in Quake3, TNT2 based boards take a performance lead with higher detail and resolutions, due presumably to a better OpenGL ICD.
Look out for the faker!
One word of warning, there is a TNT2 imposter out there, the TNT2 M64. While this current card performs quite fine in older games, the current games are going to smack this card down like the ugly stepchild it is. M64 stands for the 64bit memory bus the card has, which is half of what the normal TNT2 and V3 use. This basically means that in any game with a large amount of textures, the M64 will run a lot slower than a regular TNT2 - sometimes as slow as the original TNT.