In reply to armus:
This depends if you are using DVI-D or DVI-A. DVI-D is a completely digital signal, in which case, a given signal i.e. 60hz, 1920x1080px will be identical on DVI and Displayport (and indeed HDMI). DVI-A is an analog legacy connection and transmits analog images which are, in general, inferior to the digital signals provided by the above mentioned ports.
To complicate it more, however, the total deliverable pixels on DVI-D is lower than on Displayport and HDMI. Displayport is capable of transmitting Ultra-HD at 60hz, HDMI can transmit Ultra-HD at 30hz and DVI-D (single link) can do HD at 60hz. I believed DVI-D dual link is comparable to HDMI although I'm not sure and these connections are uncommon.
Given a choice of both, use the Displayport. If you're buying new hardware, buy with Displayport or HDMI 2.
EDIT: P.s. Displayport and HDMI carry audio. I believe DVI does not.
Post edited at 18:11
