Why i cannot add custom resolutions to my Samsung 215TW?

[DG25]

My 215TW has a very limited nr of resolutions above 1024x768: 1152x864; 1280x960; 1280x1024; 1600x900 and 1850x1050 (native). I want to add more 16:10 resolutions, like 1440x900, but when i add it, it says "cannot add this custom resolutin". Why? What am i missing?

 

[Manny Calavera]

Its lilkey the drivers.Try using Powerstrip and or Ultramon.