Over the past week we've seen a deluge of Counter-Strike: Source performance articles. For the most part, coverage has focused on graphics cards, but there's more to the Counter-Strike: Source performance story than pixel-pushing power. In addition to higher polygon counts, bigger textures, and fancy shader effects, CS: Source also features a surround sound audio engine that wraps in-game audio around five speakers. Unlike the DOOM 3 engine, which currently processes positional audio on the CPU, the Source engine appears to take advantage of hardware 3D audio acceleration. In theory, leveraging sound card resources to crunch positional audio calculations should free up CPU resources and improve overall performance, but is there really much of a performance difference between audio implementations? We've rounded up nine different sound cards to find out.