Most sound devices (onboard or not) only have one A/D converter. That means that they can only record/input from one source at a time. Anyway, it is not recommended to be gaming (or doing anything else for that matter) on a PC that is performing an audio recording. Otherwise, small glitches (or dropouts, depending on the audio driver's preference) may appear in the recording.
FWIW, some audio devices like Realtek's ALC888 have two A/D converters and can thus record two things simultaneously (dropouts could still be an issue if you're running the CPU hard, though).
FWIW, some audio devices like Realtek's ALC888 have two A/D converters and can thus record two things simultaneously (dropouts could still be an issue if you're running the CPU hard, though).
