I have problem with my dual screen-setup on Linux Gentoo (Nvidia GeForce 9650M GT,nvidia drivers version 275.09.07). External monitor is connected to laptop with HDMI. I've tried to set "Twinview" in nvidia-settings frontend and manually in xorg.conf but unfortunately everything scales between two monitors (windows, wallpaper, etc). X log says, that xinerama native extension is loaded on X start and MetaModes in xorg.conf seems OK. Even separate X screens setup with xinerama enabled causes scaling (with no xinerama everythins seems OK, but i can't move windows between monitors).
Here is my xorg.conf for TwinView setup: http://pastebin.com/CsLSybgU
And here for separate x screens: http://pastebin.com/gcsUEjff