my video card is an integrated Radeon HD 4200.. It has a DVI and RGB/VGA ports..
The Vizio only has RGB/VGA in.. When I set to duplicate displays, I can't get a full 1920x1080 on both.. The Radeon lowers the resolution to 1280x720, but the Vizio doesn't support this resolution on the RGB/VGA port..
So, instead of buying a whole new video card etc etc, I'll just split my 1920x1080 DVI signal into two HDMI with audio.. That should do what I want and put no more load on the computer.. and hopefully be cheaper than a new video card that does the same!