Get a new GPU (980Ti), or a 2nd 290/290X. Then get a new monitor (1440P 144Hz, or 4K).
With your GPU, i7 6700K platform is a total waste when an after-market 980TI smashes the 290X. Before you even get to a 1440P monitor or 980TI level of GPU performance, you shouldn't even be thinking Sklylake unless you upgrade on the very cheap after selling the 4790K platform.