I speak from several years of personal experience with a heavily overclocked Athlon 760k. The 880k isn't all that much better than my 4.8ghz 760k in terms of raw performance or architecture. I've paired it with an R7 240, HD4870, HD7950, HD7970 GHZ edition, and my current R9 380x, and beyond the HD4870, framerates didn't improve (at 1080p) at any settings with the vast majority of games I tried. Since most of the games I do play are not widely known and thus relatable, I used the original Borderlands as a comparison. It's also the one game I've played on the most platforms. The Witcher 3 also isn't particularly CPU heavy, thus making it a poor comparison. Once you've tried playing something like Planetside 2, Arma 3, H1Z1, TERA, Blade and Soul, Dirty Bomb, Skryim, or even the relatively lightweight Warframe on any piledriver or bulldozer CPU, you'll quickly realize where the shortcomings of those architectures are.
TL;DR Benchmark charts are great generalizations, but personal experience speaks volumes.