Just overclocked it to around 4.4-4.6 GHz and it'll be perfectly adequate for gaming and light productivity tasks. I used to run a mini-ITX system with an 3570K @ 4.4 GHz and a GTX 780 Ti and it ran pretty much all games just fine, especially if you're playing on higher resolutions. Also there is no reason to choose a Haswell proc right now over a Skylake proc as the pricing is basically the same (a quick look at Newegg and you'll see the 4690K is only $20 cheaper than the 6600K, which likely will change in a few months) and of course motherboard pricing is pretty similar as well. So unless you are buying used there is no reason to choose Haswell over Skylake especially given all the improvements that Z170 brings over Z97/87.