T420 - Unable to get max resolution of 2560x1600 via DisplayPort using Optimus video

[JameZ]

Question

When connecting the laptop to an external monitor via DisplayPort, the maximum resolution available is only 2048x1536 on the Nvidia Control Panel.

Answer

--------------------------------------------------------------------------------
CHANGES IN THIS RELEASE
  Versions 8.17.12.7593  (NVIDIA Graphics Driver)
           1.2.23.3      (NVIDIA HD Audio Driver)
           8.15.10.2321  (Intel Graphics Driver)

[Important updates]
  Nothing.

[New functions or enhancements]
  Nothing.

[Problem fixes]
- Fixed an issue where the external monitor that was supported up to 2560x1600
  was only set up to 2048x1536.
- Fixed an issue where Internet Explorer 9 (IE 9) might crash while loading some
  web pages.

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Windows 7 32bit -> Driver here

Windows 7 32bit -> Text here

Windows 7 64bit -> Driver here

Windows 7 64bit -> Text here