Ja, die entsprechende ISO-Vereinigung schrieb dazu:

DisplayPort versions are backwards compatible, no problem there.

070's DisplayPort 1.4 will work with 1.2v monitor.
As for cable, use the cable the monitor comes with to get the most out of your monitor. There are standards in cables that you should be aware of. http://www.displayport.org/cables/how-to-choose-a-displayport-cable-and-not-get-a-bad-one/