HDMI Display Card (Pic+Sound)

How do I know the display card with native HDMI port can carry both picture and sound?
or all native HDMI display card already support transmits of pic+sound?


Is that means only ATI card can carry sound via HDMI cable?


Oh, it's too bad. I got an ATI card before but no picture show on my Sony LCD TV (DVI ->HDMI), but the Geforce card works fine. : (