This case isn't isolated to the Xtreme Audio Notebook. In fact it's a known bug with all EAX 3.0+ cards be it notebook cards or PC expansion cards.
The explanation would be that: EAX 3.0+, unlike being a stream of audio data to be processed for reverb/echo effects (or other EAX effects), is transported in the form of blocks.
When an audio card has to playback simple wave output (as in music/videos, etc) there is no processing to be done and the audio data moves in the form of a stream from the system to the audio device. However during EAX processing, (that is upwards of EAX 2.0), the data moves in the forms of blocks, each block of data is perfectly synchronised to other outputs like the video (when gaming). When you task-switch, the video-output of the game is disturbed. The application skips several frames, the video and audio lose synchrony and as an aftereffect, the sound gets garbled. Garbeld as in: 1. There is a disturbance in the balance of stereo output. There is choppy output.
This affects audio input as well, input as in any analog/digital input because while an analog input (like say from a microphone) is perfectly a stream, the audio device cannot transport as stream and blocks simultaneously so block transfer takes place, unless the audio device's archtecture has seperate DAC and ADC. Most audio devices have combined DAC and ADC in a single chip, while the chip has seperate circuitry for DA conversions and AD conversions, the convertors share the same clock generator. In case of AC'97 codecs, the AC in the southbridge uses the SB's clock, could be similar with Intel Azalia HDA.
