I7 4790k with no doubt. While an I5 4690k at 4.5ghz may perform better in games than an I7 4790k at 4.4ghz, ther performance difference is going to be well below 0.5%. Maybe one frame per 5 seconds, at best measurable but definitely not noticeable.
While the I7 4790k is performing about 15-20% better in rendering, engine building, compiling and other stuff. You can also oc on b85 boards, by the way. I wouldn't go further than 1.2v (~4.6ghz) but it's doable. But currently, theres so little sense in it right now that im running my I7 4790k on 4.0ghz for everyday use and only quickly swap to 4.7-4.8ghz when I'm rendering or compiling large projects. ~200.000 lines of code, more when thinking of included headers. Or an hour of video length.