I have been struggling for quite a while, and I hope one of you can shed some lights on my issue. I am using Xubuntu 13.10 (Ubuntu 12.04LTS behaves the same way, higher version wouldn't install, LinuxMint didn't install, Fedora didn't install). I am trying to set extend display for two dell monitors 1900x1200. It works great when in mirror mode, but I just cannot extend the display. Either one monitor goes to sleep and the other is unresponsive, or both work but are unusable. This is a link to the picture of my monitors in mirror mode This is link showing what happens after I try to extend the desktop I get the same results if I use aRandr or the built in configuration utility. I have an ATI Radeon X300 card. I cannot use proprietary Catalyst drivers (I would have to use the legacy ones, which would force me into using much older version of the OS). Extension is possible with Windows. I am hoping someone can come up with tweaks that would allow me to run an extended desktop. I truly love Xubuntu (and Ubuntu, unfortunately, Unity is a bit too heavy for my old PC, and I have to run in 2D mode, so 12.04 is as high as I can go). I have tried everything I could find online, but nothing worked thus far. I believe some configuration or something I am missing might work. Please, if you have any idea, do not hesitate. Thanks guys.