Dissecting the drivers
With Asus and Auzentech spinning unique sound cards based on the Oxygen HD and X-Fi audio processors, it's only fitting that the drivers for each get a little remixing, as well. Auzentech has arguably done the least on this front, repackaging Creative's existing X-Fi drivers without so much as changing the skin on the interface. But that's not necessarily a bad thing.

Creative's audio console is excellent, coming in three flavors for game, entertainment, and audio creation modes. Each offers a unique mix of features and settings to manipulate, dedicating the X-Fi's formidable hardware resources accordingly. Users can switch between these modes on the fly, as well.

Of course, Creative's drivers have often been accused of being bloated—and fairly so. That isn't a problem for the Prelude, though. Auzentech's repackaged X-Fi drivers cut out most of the fat and even include a base driver-only install that ditches the fancy audio consoles in favor of a much simpler interface.

In an attempt to provide a streamlined driver package for enthusiasts, Auzentech may have cut a little too far. We don't miss the bloat, really, just the Creative DVD-Audio playback software that's a part of the standard X-Fi (and even Audigy2) install package. For a sound card capable of playing back high-definition audio, DVD-Audio is a no-brainer, and Creative's player appears to have been left on the cutting room floor.

One extra that Auzentech has included is Creative's ALchemy software for translating EAX calls to OpenAL commands that can be accelerated in hardware under Windows Vista. ALchemy is hardly a silver bullet for EAX in Vista, though. The current list of supported games is distinctly lacking in new titles. F.E.A.R. appears to be the most current, and the vast majority are several years old at least. Even Battlefield 2, an older game that was a poster child for the X-Fi's EAX 5.0 Advanced HD hardware acceleration, is absent from the list. At least in its current form, ALchemy's benefits appear to be confined to games you might find in the bargain bin, if they're even for sale at all anymore. Asus also does some driver repackaging for the Xonar D2X, but this includes a major facelift. The entire driver interface is unique to the Xonar, consolidating control over everything from equalizers, speaker configuration utilities, and virtualization schemes into a single control panel. As with the X-Fi, the drivers can be switched between modes covering audio creation, multimedia playback, and gaming, but the actual interface doesn't change. Asus also has its own spin on ALchemy called D3D GX.

Available with the latest Xonar drivers, D3D GX is another DirectSound wrapper with full support for EAX. Well, EAX versions 1 and 2, at least—that's as far as the Xonar goes. Like ALchemy, D3D GX's list of supported games is dominated by older titles. There are a few odd additions, as well, such as Quake 4, which already has native support for OpenAL. Either way, the Xonar's lack of hardware acceleration for 3D audio, combined with its support for only the most basic EAX levels, blunts much of D3D GX's appeal.

Apart from D3D GX, the Xonar's drivers don't include much in the way of extras. Features like real-time DDL and DTS encoding are already built into the Oxygen HD, so there isn't much that really needs to be added. Asus has included some fancy echo cancellation that Skype users should appreciate, though; it works quite nicely.