The monitor might have the wrong EDID information.
Had same problem with not being able to obtain better than 1440x900 resolution with Samsung T220. Downloaded latest NVIDIA update to version 184.108.40.206 then changed refresh rate to 60hZ.
At the lower refresh rate the full 1680x1050 resolution was available. Monitor works great now. Hope this helps.
Use Powerstrip software to update the EDID information.
Or update edid via http://www.geocities.com/jgeneedid/EDID_Writer.zip
for this u have to run DOS, i will try make bootable flash drive with DOS...
NOTICE: u should know that if u modify edid in your panel u lose warranty!
before u run command for rewriting edid go to service menu on monitor, it will disable write protection for while
how to enter service menu:
1. Set contrast and brightness to 0
2. Press the « Menu » button
3. Press the « Source » button for 5 seconds (the second one on the right)
for exit just switch panel off...
I flashed the EDID in my Samsung T220, and it did the trick
I copied the Raw data from his post into a file using HexEdit, and flashed the monitor using PowerStrip v. 3.83. (I ordered version 3.85, but it didn't arrive in my mail until much later).