Truth be told you won't see too much of an improvement, even by going with Skylake for the i7, and virtually none by using the Haswell/Devils Canyon parts, AND you'll need to change the motherboard as well as the memory if you go via the Skylake/DDR4 route.
Plenty will probably run down the R9 390, but it's a good part, not sure about 8Gb of onboard memory though.
Obvious alternative is the GTX970, it and the R9 390 trade blows at 1080 res while the R9 is a tiny bit faster at 1440 res.