I have an issue with the proprietary Nvidia drivers and XFCE that appears neither with Intel graphics cards nor with any other desktop environments.

When moving windows or watching movies, the section of the screen that is damaged by the window move will have an ugly and annoying checkerboard pattern flickering in it when it refreshes. This also happens when scrolling long web pages in Iceweasel. Here's an example video:

https://www.youtube.com/watch?v=3VE5p2rgOjM

I think this pattern might be related to another issue, I'm not able to set 60 Hz refresh rate at 1920x1200, it only goes to 59.95 Hz. On resolutions below that, I can set 60 Hz.

The card is an Nvidia GTX560, screen is connected via DVI. I tried both DVI ports and the result is the same. The nvidia driver comes from Debian's package version 340.76-5.

The built-in Intel card does not have these problems, it sets 1920x1200@60 without problems and has good vsync, no tearing, no checkerboard flicker. It is usually disabled completely, I only enabled it for this test.