Not with the current mining craze. Maybe once the Vega56 hits and if it can be under £400,we might also see deals on the GTX1070 too.
Also 1080p 100HZ is not so easy to do in modern games,if you whack the settings up for more modern games although I have an old IB Xeon E3 1230 V2/Core i7 3770:
http://forums.hexus.net/reader-revie...enchmarks.html
OTH,you have an overclocked CPU SKL though - I do probably need a faster CPU at some point. So with a newer CPU than mine and stupid settings turned down,I suspect a Vega56/GTX1070/GTX1080 would make it doable.
If it were at 1080p,60FPS,I would have recommended an RX470/RX570 at £160ish if it were not for the blasted miners. The RX470 I had access to overclocked really well with very few tweaks.