Why would I need discrete graphics in a T-series Thinkpad?

First being a premise that I don't game at all. The most intensive app for me that uses 3D acceleration would probably be Google Earth, perhaps the new Adobe software. Also hardware acceleration for H.264, VC-1 and HD grade MPEG-2.

What good would discrete graphics provide me? Can the integrated graphics pump 2560x1600 through the DVI/DP on a docking station, given the right cable?

 

if you don't game or use workstation 3d applications
then you don't need discrete graphics
the integrated graphics will work great for you!

 

I looked at one of the integrated cards that lenovo uses, 4500MHD and found some specs about it. So the answer is NO. you cannot go that high with a integrated chip. VGA or DVI will yield the same max res. The max res is only 2048x1536


http://www.intel.com/Assets/PDF/datasheet/319970.pdf
Analog Display (82Q45, 82Q43, 82B43, 82G45, 82G43,82G41 GMCH only)
— 350 MHz Integrated 24-bit RAMDAC
— Up to 2048x1536 @ 75 Hz refresh
— Hardware Color Cursor Support
— DDC2B Compliant Interface

Digital Display (82Q45, 82Q43, 82B43, 82G45, 82G43,82G41 GMCH only)
— SDVO ports in single mode supported
— 200 MHz dot clock on each 12-bit interface
— Flat panels up to 2048x1536 @ 60 Hz or digital CRT/HDTV at 1400x1050 @ 85 Hz
— Dual independent display options with digital display
— Multiplexed digital display channels (supported with
ADD2 Card).
— Supports TMDS transmitters or TV-Out encoders
— ADD2/MEC card uses PCI Express graphics x16
connector
— Two channels multiplexed with PCI Express* Graphics
port
— Supports Hot-Plug and Display