Creative has all but dominated the PC sound card market, in no small part thanks to its prowess with hardware-accelerated 3D audio. The EAX positional audio framework born from the SoundBlaster line became the de facto standard for 3D audio in games, giving Creative a distinct advantage over its rivals. Creative licensed EAX, of course, but it kept competitors at version 2.0, limiting them to 32 concurrent 3D voices and standard-definition sampling rates and resolutions. Meanwhile, Creative extended EAX to version 5.0 with support for 128 simultaneous voices and high-definition resolutions and sampling rates.

Despite its positional audio dominance, Creative has faced increased competition of late, largely from sound cards based on C-Media's Oxygen HD audio chip. Microsoft's decision to drop hardware acceleration for DirectSound 3D audio in Vista has also posed a challenge to the SoundBlaster monopoly by blunting some of EAX's appeal. All the while, motherboard makers have diligently worked to improve the quality of onboard audio solutions, creating a perfect storm that has spawned more PC audio choices than we've ever seen before. Interestingly, two of the most recent additions to the sound card ecosystem use existing audio chips. Asus' new Xonar D2X, for example, is based on a tweaked version of C-Media's Oxygen HD. More interestingly, it comes with a PCI Express interface, finally providing fodder for the scores of empty PCIe x1 slots that dot the enthusiast landscape. On the other side of the fence we have Auzentech's X-Fi Prelude, which is the first third-party card to employ Creative's X-Fi silicon. The Prelude uses a custom board design and upgraded components in an attempt to wring better sound quality from the already impressive X-Fi audio chip.

The Xonar and Prelude both target the high end of the desktop sound card spectrum, so it's only fitting that we face them off against each other in Windows Vista. Read on to see how they fare in a range of gaming, signal quality, and subjective listening tests.