Currently I use core i5 system 2320 @ 3.0GHz with x86-64 bit architecture using Ubuntu 12.04. I intend to buy a Graphics Card which supports to work on multiple monitors for multiple workspaces. Any suggestions which graphics card to buy and how to configure my system for this? I have already installed Compiz on my system.
Did you try some 3D software with your xinerama setup ?
In some[which?] implementations, OpenGL (3D) direct-rendering only works on one of the screens. Windows that should show 3D graphics on other screens tend to just appear black. This is most commonly seen with 3D screen savers, which show on one of the screens and black on the others. The Solaris SPARC OpenGL implementation, ATI Proprietary Linux driver and nVidia Proprietary Linux driver all support hardware accelerated rendering to all screens in Xinerama mode.