Games were played to determine the quality of the sound, but also to measure the impact on gameplay. FRAPS was used to count frames. Since manually playing a game suffers from exact repeatability, a minimum of 5, 60-second runs each, of a well worn path and set of ‘activities’ in-game is used to get a good average.

The machine used was configured as such:

• Core 2 Duo E6600 CPU
• Intel 975X
• 2GB Crucial DDR2 800
• EVGA nVidia 8600GT
• WD 150GB Raptor HDD
• Intel/SigmaTel integrated HD Audio
• Asus Xonar D2X
• Creative Labs Xtreme Audio PCI Express
• Windows XP Pro SP2
• Bioshock
• Call of Duty 4
• Battlefield 2142

There are a few notes to be aware of. First is that we did not test any of these games with Vista, and as such we did not test the controversial DS3D GX technology Asus developed to enable EAX extensions with Vista.

Bioshock

Ah, 50's kitsch underwater, set to a spooky ambiance, a soundtrack to die for, and water, water everywhere, this is Bioshock.  Don't tell me how it ends, though--I just keep playing the same passageway over and over and over again.  All cards had issues with EAX, so for the benchmarks it was disabled.  However, sound crackling with EAX appears to be a Bioshock-only phenomenon, since BF2142 had no crackles at all.  BF2142 doesn't have Mr. Bubbles, though... The cure was to disable EAX for the benchmarks. 

Bioshock is a lovely game, powered by the Unreal 3 engine, with lovely sounds.  It does pose a challenge for the D2X processing all that sound just a little slower than the other cards, but overall it didn't affect gameplay too much. 

Subjectively speaking, the D2X did a smooth job.  The X-Meridian tends to emphasize the ambient bass rumble, while the SigmaTel (Intel HD audio) emphasized nothing and sounded a little weedy.  The D2X probably did the best job with the echoes, which are everywhere, not too little and thankfully not too much.  The X-Prelude was somewhere between the D2X and the X-Meridian, and the X-Audio didn't really do anything offensive nor memorable.  In this game, I leaned towards the D2X, where the crisp and clean sound really makes the game sounds stand out and much more immersive.

Call of Duty 4

Call of Duty 4 is truly a magnificent piece of gaming, however short.  I agree with Hilbert that the sniper level with the ghillie suit, traipsing around Chernobyl, avoiding radiation, meanwhile taking out bad guys with the M107, is the best sequence ever put into a video game.  I also liked the 'death from above' level too, but YMMV.

CoD 4 does not have the best audio engine in the realm of PC games.  Some games use positional audio to help the player find enemies, and enhance immersion.  We like immersion.  CoD 4 seems optimized for consoles, and there really isn't much difference in surround modes.  However, plain old stereo worked great.

Not the best showing for the D2X, unfortunately.  Fortunately, it's still very playable.  But, we rest our case when you actually hear the game through the D2X.  It's an assault on your ears, and the D2X certainly provided that! 

Battlefield 2142

Battlefield 2 and it's 'sister' game, Battlefield 2142, are just two of a handful of games that can make use of the X-Fi's 'Ultra-High', 128-voice, mode.  Luckily the D2X can also process 128 voices, so it was enabled for BF2142.

One thing we did notice in our original X-Meridian review was that even though the card supported the Ultra 128-voice mode, it did exhibit some crackling with the sound.  The Xonar D2X had none of that, it was smooth, playable, and the soudns just suck you into the chaotic world BF2142.

First let's explore the DS3D GX technology, where it really has a chance to show off with Battlefield 2142.  Before DS3D GX:

And after:

The essence of the technology is to allow games to detect the D2X as a sound card with EAX 3, 4, and 5.  These EAX modes are present only in Creative products, such as the X-Fi Xtreme Gamer, supporting the latest EAX 5.  Since Creative doesn't license EAX higher than 2.0, this naturally miffed Creative something fierce.  This also means that the DS3D GX technology doesn't actually do any of the EAX processing higher than 2.0, it just tells the game it can.  And a good time was had by all:

I did the borage of FRAPS for, oh, a week straight to get these numbers.  And then after I saw them, I did it again, just to make sure.  Yup, the D2X is actually faster with DS3D GX enabled than on the 'medium' (software mixing/32-voice/no EAX) settings.  I'm not too surprised, but it is very interesting that you can see a few FPS gain with the D2X in BF2142.

The only problem is that I did not notice much of a difference in sound between the software/32-voice mode and the DS3D GX powered Ultra 128-voice mode.  They sounded nearly identical, in fact.  One of the things the X-Fi can do is EAX 5.0 on the fly (with about a 15% performance penalty), and the immersion in the game is so very alluring.  You can hear things like support pillars blocking sound, gunfire ricochets, and that disturbing hiss of a grenade.  You don't hear that with DS3D GX.  It does do what it's supposed to do, subvert EAX detection, but then again, it doesn't actually do any of the more interesting EAX effects either.  I guess I'll wait for Asus to reverse engineer EAX 5, or wish for Creative to open source EAX.

So the D2X won't enhance your gameplay by a whole lot of frames-per-second, unless you play a lot of BF2142.  There are better choices on XP systems, obviously.  However, and it's a big however, the sheer audio quality will increase immersion and enjoyment.  In my opinion this would make the D2X better sound card, however, the missing environmental effects.