The same adapter chances are yes but it fine and he runs 1440×900 on his 17 inch monitor no problems am not sure if you have the same adapter and he has an xbox 360 he runs 1440×900 on his 17 inch monitor no problems am not sure if you have the same.
The XBox 360 can support resolutions of up to 1920×1080 (aka 1080p High Definition) if you use either the HDMI cable or the HDAV VGA cable, provided that your monitor can go up that high.
Hope this helps.