GeForce FX in Source engine investigated
I had an interesting phone conversation with Brandon Bell over at the FiringSquad after the publication of our CS: Source video stress test article. We were puzzling through the GeForce FX cards' unexpectedly solid performance and whether the Source engine was using DirectX 9 with them. I added some screenshots to our CS: Source article showing the difference between DX8, the FX, and DX9 in an attempt to figure things out, with some success. I learned the FX cards aren't doing straight-up DX8.0, at least. Brandon went the extra mile, though, testing the various rendering paths on FX cards. The results aren't entirely conclusive, but he surmises that the FX cards are using DirectX 8.1 and can't be coaxed into DX9. The screenshots and benchmarks would seem to support that conclusion.