I bought an xfx Geforce N640 video card and installed it with driver 313.18 in my Ubuntu 12.04 64 bits. The tearing level on my screen is bad, and in another question here (How do I stop video tearing? (Nvidia prop driver, non-compositing window manager)) a guy recommends changing the powermizer setting to maximum performance. The problem is that nVidia settings don't remember my choice and return to adaptive every time. So, how can I fix this via command line in xorg? thanks!