Our colleagues from TweakTown received a bunch of information about the Asus Xonar audio cards.
They write the Xonar cards are based on a CMedia chipset. Unfortunately they won't have some of the latest EAX features but according to Asus the 118dB SNR will beat just about any other consumer sound card. It looks like the first versions of this card will be released as PCI cards, PCI Express x1 cards may become available later.
The Xonar cards feature 192KHz/24Bit for all input and outputs, real-time Dolby Digital & DTS surround encoding for up to 7.1-channels, ASIO 2.0 drivers and a mini MIDI connector.
The Xonar cards also have a nice feature called ALT (Analog Loopback Transformation):
This is a direct connection between the DAC (Digital to Analog Converter) and the ADC (Analog to Digital Converter) and allows for an easy way to backup DRM protected audio files by re-recording them in a DRM free format. The neat thing with how this is done is that it allows for minimal loss in audio quality
You may have noticed that the card has a strange cover, this isn't a cooler but an EMI shield. According to Asus the EMI shield improves audio quality by 4-6dB.