I am thinking about purchasing the STRIX 1080 to upgrade from my STRIX 970. Does the card work with the motherboard that comes with the 8700? Will the card fit (it is 11.73 in)? Will I need a better power supply (I have a 600w PSU installed)? Has anyone tried installing this card into an 8700 before?
Apparently, the Asus Strix 1080 and 1070 have the same dimensions. The Asus Strix 1070 is reported to fit, though barely so, in the XPS 8700. See the statements and responses by poster Justme2016, at the following link:
So far, it appears that there have been no reported BIOS incompatibilities between the XPS 8700 and any of the GTX 10xx series of graphics adapters. For a list of some user upgraded XPS 8700 systems using GTX 1080 cards, see the following link:
According to the Asus web site, the Strix 180 has power consumption of "up to 300W" (whereas a non-overclocked XPS 1080 has a TDP of only 180 watts). Considering that, and depending on the other components of your system and the condition of the current PSU, a 600W PSU may not be adequate or provide a sufficient margin. I would recommend an upgrade to at least 750W (or more, depending on what other components are installed). Also, note the tight clearance requirements for larger PSUs in the XPS 8700 case.
You may better estimate the projected power supply requirements of your system by use of the following calculator: