GTX 1080 with Qnix2710 - DVI to DP/HDMI and OC?

Hey folks.

so the GTX 1080 has only 1 DVI port, a couple of DP and one HDMI port.

I am running 2x Qnix 2710 which are able to run at 120hz.

So due to the new GPU I am forced to hook it up either at the DP or HDMI. If I hook it up on DP (dvi to dp converter) I cannot overclock it, even 5hz more results in a blackscreen. On HDMI (dvi to hdmi cable) there is no screen at all.

Is there anything I am missing or is OC not possible via DP?

These are the cables I got:

DVI to DP adapter
https://www.amazon.com/gp/product/B00OQQ...UTF8&psc=1

DVI to HDMI:
https://www.amazon.com/gp/product/B014I8...UTF8&psc=1


Do you think this cable here would make any difference? DVI to DP cable
https://www.amazon.com/gp/product/B00ODD...UTF8&psc=1