Why T420s with Nvidia Optimus mode activated can not output resolution higher than 2048x1536?
My T420s model number is 4173-RA5 with display card NVIDIA NVS 4200M, and power adaptor 90W, without docking.
When I connected my laptop using a Display Port cable(both ends) and output to DELL 3008WFP monitor, it could display up to 2048x1536 only as the maximum solution, as opposed to 2560x1600.
Is there any setting or configuration that I have done wrongly?
The T420s with Nvidia Optimus mode activated is capable of supporting 4 displays of 2048x1536 when used with the appropriate Mini Workstation Dock Series 3.
However, if you want to support resolution above 2048x1536, for example 30 inch WQXGA or 27 inch qHD resolution, then you have to switch to discrete graphics mode only (within the BIOS config menu under display option). This will allow you to support up to 2 x 30 inch WQXGA screens.