I have a laptop with a 1920x1080 HD screen and an external monitor with the same...it works awesome, does everything I need or dream of. Laptop is an HP ENVYx360 with special ordered screen. -S
 

as far as I know there is no quality difference between HDMI, DVI or VGA, if it drives your pc's resolution it's the same quality.

I can tell the difference between VGA and HDMI on a 22 inch 1680x1050 screen I have. Don't think there's a difference between HDMI and DVI, except for the supported resolutions and cable length.

Regardless of any differences, all three work fine for use with Sonar.
 
I have run VGA and HDMI to 2 monitors for over 2 years now, with no difficult whatsoever, AND, the HDMI connection routes Windows sounds outside of Sonar to the 32" HDTV's speakers, making it SUPER easy to have Sonar get exclusive use of my audio interface, and the Windows Default Audio Device for all of the rest of sounds shares the HDMI cable with the video signal, so it's a win-win.
 
Bob Bone
 
Bob