Intel i-7 6700k is extremely adequate for a CPU considering most games hardly take advantage of the I-7's hyperthreading technology.

The Radeon R9 Fury X2 could handle 4K textures, but I wouldn't try it on a true 4K monitor if they even have those available yet. (4096x2304) My monitor's native resolution is only 2560x1440.

I'd save your breath on using 4K native resolutions and just dynamically supersample your image and then downsample it back to your native resolution which is hopefully 1080p.