When using monitor in TwinView, the OS doesn't recognizes it's native resolution, why?

[Ric Moore]

On Wed, 2011-08-03 at 18:48 +0200, jeremy, thomas wrote:
> "Monitor A": Samsung 940N 19" LCD [VGA connection]
> "Monitor B": Samsung 940N 19" LCD [VGA connection]
> VGA card: Nvidia Geforce GT220 [has 1 VGA, 1 HDMI, 1 DVI]
> So I'm using a "DVI to VGA" converter.
> 
> Under Windows7: The OS recognizes the 1280x1024 native resolution in
> both monitors, hurray!
> 
> Under Ubuntu 11.04: The OS recognizes one of the monitors ("Monitor
> A") as a Samsung, OK! (resolution is good too!). BUT: the other
> monitor ("Monitor B") is recognized as "Unknown", and uses 1024*768.
> (the "other" monitor is the one that's with a DVI to VGA converter -
> "Monitor B"). I installed the NVIDIA driver too, but it still
> recognizes the second monitor - "Monitor B" (with the DVI to VGA
> converter) as it would has a maximum resolution of 1024*768.
> 
> Question: How could I "tell" Ubuntu to use the "other" monitor -
> "Monitor B" with 1280*1024 (the native resolution)???

Use the nVidia X Server application to set it up, and write out the
new /etc/X11/xorg.conf file. <----don't forget to do that, which should
resolve the resolutions bit as well!! 

Then use your system preferences bit to complete the desktop settings.
You should be good to go, that is how I set up mine. I set up my display
to be one display 2X wide across both monitors. Works perfectly for me. 
-- 
My father, Victor Moore (Vic) used to say:
"There are two Great Sins in the world...
..the Sin of Ignorance, and the Sin of Stupidity.
Only the former may be overcome." R.I.P. Dad.
Linux user# 44256