Problem with color changes

Hello, I have a problem.
It's not super noticable unless you're looking for it, but it's there.

When there is a transition in some colors, for instance the starting blueish screen for windows 7, when you are starting up the computer. On the left side, it goes from light blue to darker blue, and the transition between these colors are not smooth, you can see the edges, like theres 10 different colors before it gets to the right one.

It is a bit hard to explain, I will try do better if this wasn't clear enough, it also happens in games, most noticable in the sky.

I'm not sure it's a video card issue but I have run driver sweeper and a clean install of the latest drivers and nothing changed.

I have a gtx 295 if it matters.

This is a print screen of the problem.
I made a marking around the part I mean.
The game is fullscreen, the other image is my other screen.

http://img7.imageshack.us/img7/236/colortransition.jpg

Thanks