I have my doubts a dell 460W psu would be adequate to run a GTX 770 and if it even comes with two pci-e pins.
Well it does come with the required pcie power connectors.
Only problem is GTX 770 needs more juice then a 500W max psu.
You could probably run a GTX 760 with the stock psu.
Very little info on how long of a gpu that chassis will accept though.
Secondly I would be concerned if the XPS 8700 chassis can accommodate a gpu over 10.5" long.
I'm going with a nah based on my experience.