To approximate real-world frame rates, I ran our test system at the highest in-game graphics detail levels, 4X antialiasing, and 8X anisotropic filtering at a relatively high resolution of 1280x1024. Dropping the display resolution down to 1024x768 and turning off antialiasing and anisotropic filtering didn't really improve frame rates, so our graphics settings aren't going to be the bottleneck here.
This one's all Creative, folks. Led by a couple of Audigy2 cards, the four Creative cards offer better in-game performance than any other audio implementation we tested. With new cards like the Audigy2 and Audigy2 ZS, that's hardly shocking. However, it's a little embarrassing that the original Audigy comes out ahead of the rest of the pack. Getting beat by an ancient SoundBlaster Live! would be embarrassing, too, but since the Live! is only capable of four-speaker output, its score isn't directly comparable.
Trailing just behind the Creative posse we have Hercules' Gamesurround Fortissimo III, which, despite its age, manages to knock off all of our newer Envy24-based cards. Of the Envy24 cards, the Mad Dog Entertainer offers the best in-game performance, followed by Philips' new Ultimate Edge. The M-Audio Revolution 7.1 brings up the rear with our VT8237/VT1616 integrated audio; both are more than 10% slower than the Audigy2 ZS.
Our three Envy24-based cardsthe Entertainer 7.1, Revolution 7.1, and Ultimate Edgeall share the Envy24's lack of hardware 3D audio acceleration, so it might seem a little odd to see them score differently in CS: Source. However, I should note that each of the cards uses a different driver. M-Audio and Philips offer their own drivers for the Revolution 7.1 and Ultimate Edge, respectively, while Mad Dog uses VIA's reference Envy24 drivers. Each driver may deal with 3D audio a little differently, which would explain the slight performance differences between the three cards.