depending your vga card & vga driver it self. if support at all resolutions. much better if your vga card support with HDMI, so transferring data, color, etc to your lcd more fast then using old vga cable. remember playing on highest resolution (720i, 720p, 1080i, 1080p / HD) need more power from your cpu.
alternative method.
1. try modify your system environment (SystemEnv.txt) in user folder. change VIDEO_WIDTH 1280 & VIDEO_HEIGHT. if not work, use default on graphic option in dbo launcher.

2. download the latest update for your vga card. if that latest update not supported, you can try mod your update with vga mod tool.
www.hardwareheaven.com/modtool.php

*after mod my vga update. i can get 2048x1536 resolution.
http://superuser.com/questions/39307...s-a-pc-monitor
http://forums.whirlpool.net.au/archive/992872
Thanks..