it always uses the soundcard. All that changes is where the sound is routed to. You may have to tweek a setting or two to get ALL of the audio to output via HDMI. often anything not in HD audio, like surround sound, will be output to the spdif or regular audio jacks. It may be as simple as removing those output types from the audio control panel to force all audio to use HDMI. Alot fdepends on what your board will supoort over HDMI.