5k 6Hz on DELL 7730 with P3200

Hi all,

It says here that ths machine is capabel of 5k 60hz with the quadro P3200, I am able to get only 30Hz...

https://www.dell.com/support/manuals/de-de/precision-17-7730-laptop/precision_7730_setup_and_specs/video?guid=guid-a615a91f-1cbf-43d0-845b-aec6eb03f40f&lang=en-us

Do you guys know what "dual" and "singel" in this sheet means?

Regards Tom and thank you!