There are several trends evolving in computer games that should shape your decision when considering a new graphics card. One important trend is multitexturing support. More games are doing multipass rendering in which textures are blended together. This results in more realistic surfaces and better lighting/shadow effects. Single-pass multitexturing allows a 3D accelerator to blend multiple textures in one rendering pass. Until recently, only Voodoo2 had multitexture support - and only in Glide/OpenGL.

The RIVA TNT, with its dual texturing pipelines, has multitexturing capability, which becomes apparent in Quake II tests. Banshee boards trailed the performance of the stock PA2000 Voodoo2 card by a wide margin on Quake II, even though they ran ahead of the Voodoo2 board in many Direct3D games. DirectX6 has full support for multitexturing, so we'll likely see more multitextured games in the future. The recent trend toward dual rendering engines in newly announced chips only adds fuel to this fire.

Another trend is the movement toward richer texture sets. This is happening more slowly than we expected, but we are beginning to see titles with 20+MB of textures in scenes. Some of these titles, like Criterion's Redline Racer, were also designed with AGP in mind. The trend toward higher polygon counts has an effect, too, because more vertex data needs to be sent over the bus. The full setup engine in the most recent chips eases the problem a bit, but it's still there. Huge texture sets coupled with high polygon counts can really saturate the bandwidth of the bus. This partially explains the trend towards large amounts of local video memory. AGP version 1.0 maxes out at 528MB per second - but smaller amounts of textures need to be retrieved at any moment in time if AGP execute mode is used.

Still, the bandwidth problem has brought us to AGP 2.0 (a.k.a. AGP Pro), which doubles maximum AGP throughput to 1GB/sec. We should see the first AGP Pro boards early next year.