I am able to enjoy all of the compiz desktop effects with screen resolution set lower than native, which is 1920X1080. As soon as I switch to this resolution, when I go to change a wallpaper, the screen turns to colored lines or freezes. All other effects work fine. It is only the changing of wallpaper that causes this. I have read that the ATI Xpress 200 GFX card is no longer supported by Linux, but there must be a way to rectify this one problem. Thanks in advance.
Are you using the fglrx driver? Using the open source radeon driver might solve your problem.