I have the same problem with Ubuntu Edgy running on my nVidia GeForce 6800 GT graphics card.
The "color banding" seems only to appear on vertical gradients. Horizontal gradients are displayed ok. -- Colour depth problem on one display following upgrade to edgy https://launchpad.net/bugs/71094 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
