For some reason, when I connect 1920x1080 monitor (same resolution as laptop's screen) via DVI whole computer appears uber slow - as I am typing it in gedit there is a .6 second delay after each key press before it appears on the screen.
I connect exact same monitor via VGA and all is fast and nice.
I installed 13.04 64 bit on Thinkpad T530 with NVidia NVS 5400M. In BIOS Optimus is disabled.
This is what I see in Details->Graphics:
Driver: Intel Ivybridge Mobile