External display issue (VGA)

At my desk I'll plug 23' Samsung into my 15' 2011 Macbook pro. While the 1600x resolutions fill the entire Samsung 23' when I change the resolution to 1920x1080 I lose roughly 1 inch in the left side of the monitor and about 0.5 inches on the right side (they are just black areas sorta like a wide screen movie except on the sides).

I don't really mind this but the main issue is the picture while in 1920x1080, I get fairly faint vertical stripes, these stripes are very apparent on solid back grounds and are extremely annoying, I thought this was just a monitor issue however when my friend brought his 15' 2010 Macbook pro over and plugged into the VGA adaptor at 1920x1080, the entire screen was utilized and no vertical stripes were apparent.

I cannot correct this issue with the monitor's built in menu/setup, and I don't know of any way of adjusting this in the system preferences or anywhere else myself, so if you have any helpful advice about this subject I'd truly appreciate it!

The only reason I could think my self is that it may have something to do with the GPU change from nVidia to AMD, thanks again