The Asus Xonar D2/D2X (the X is for the pci express x1 flavour) is a fantastic audio card. Many people wonder what an add in audio card gets you, and what is meant by clearer audio. Put it this way, when I put my D2X in my pc and connected up a decent set of Altec Lansing speakers I immediatedly noticed more from my music and games. I recognised beats and patterns in the lows coming from the subwoofer which I had not noticed with onboard audio, and a less distorted treble and midrange. Another thing I notice is that the audio can now be louder but still be more accurate than before. An audio card now wont give you a noticeable increase in framerates in games, as the CPU can do most of the job. However, this card features full hardware Open AL and creative EAX emulation for better audio effects in games. Also with the driver software you can tweak many settings including microphone echo reduction, voice masking, changing LFE crossover frequency, which speakers to direct bass to, and enabling a good karaoke mode as well as the usual equaliser and effects settings.
The card does 24-bit 192kHz audio and has 118 dB signal to noise - pretty high end specs and high end capability, but of course, im not an audio robot with an oscilloscope, so cant really describe what this means. Except...It is a lot better than my on board audio and it allows me to play around with my audio settings more to get a better sound out of my speakers.
The bundled software with this card ranges a few trail software suites such as Albeton and Cakewalk. For the most part, you can bin these once the novelty of figuring out what they do is gone - if your a professional musician that uses a computer you probably have what the trial software offers, or already know what little you can learn from them without the full versions. The PowerDVD disc is handy if you dont have a decoder already. The box comes with a LOT of cables. The audio sockets also light up different colours which look great and can help with finding the holes to put you jacks in - common problem we all have. Overall im happy with the £95 purchase.
Just a word of warning, this card has trouble fitting in the top most pci-express x1 slot on most motherboards for the D2X version. If you are looking to buy this card, or upgrade motherboard after you buy one, then EXPLICITLY check for clearance of the memory module or other obstruction from the slot you want to fit this card in. In many cases the floppy disk power lead it needs will get in the way or the card will hit your memory module.