Audigy2 main features look as follows:
Audio playback in up to 24bit/192kHz mode;
Audio playback and recording in 24bit/96kHz mode;
DVD-Audio format support;
Dolby Digital EX decoding;
Sound output onto 6.1 speaker systems in movies and games;
Seven analog outputs;
THX certificate (the Audigy2 is the first audio card to have it);
New sound up-mixing algorithms CMSS 3D;
Improved signal/noise ratio (SNR) - 106dB.