Based on the screenshots and performance benchmarks, it appears that not only do GeForce FX cards default to DX8/DX8.1, but they also can’t be forced to run Valve’s DX9 path in the Counter-Strike: Source beta release. Instead, the maximum level GeForce FX cards currently support is DirectX 8.1.

Fortunately, Valve can produce most of Half-Life 2’s most stunning effects with 1.4 shaders, even the 8.0 code path looks similar, producing an image that looks quite good. As a result, you may have a hard time seeing some of the differences between the DX8.1 path and the DX9 path until you run the two side-by-side.