Manshack :
bystander :
The option is on the same screen as where you set 120hz, if you use the Windows Screen resolution dialog boxes. Right click the desktop, select "Screen Resolution" -> "Advanced Settings" -> Monitor Tab and on that page, there is colors option at the bottom. Make sure you set it to 32-bit.
Yeah it is, just tried rolling back my computer to a previous date and still have these lines in the sky. Perhaps it's a software problem and not to do with my monitor.
That is most likely the case. The game just doesn't display a smooth representation of color. If it was the monitor, screen shots would not allow it to be seen on another monitor, but it is. I looked up causes for color banding, and I found the same cause, which is lower bit color or software issues.
A new monitor tends to bring out the hawk eye in you, and you just started paying attention to it.