ST2320L banding in gradients

Hello, I recently purchased a Dell ST2320L monitor and noticed some banding on my desktop wallpapers when gradients are present.  At first I thought this was just because I was using the VGA cable the monitor came with, so I ordered a DVI-to-HDMI cable (DVI connects to my video card, HDMI connects to the monitor).  Unfortunately, that did not fix the problem and I am at a loss.  Is this just a quality issue with this monitor, or is there something I can adjust?

Thanks for your help!

For reference, this is the wallpaper I'm currently using which demonstrates the banding: http://www.wallpapers.cc/wallpapers/blue_vista_orb-1920x1200.jpg