I wouldn't put too much stock in passmark, it doesn't really represent real world performance. It scores the fx 8350 higher than an i5 yet in real world programs the i5 outperforms it. Theory isn't reality. It's a generic and loose guide at best.
I'm not sure which programs you're using, if it's encoding, gaming or what. In some programs like video encoding the 6700k has a slight advantage, in gaming almost no difference other than a couple of games. This is a comparison of the 4770k but it's clocked the same as a 4770 at stock so they're interchangeable in these bench results.
http://www.anandtech.com/bench/product/836?vs=1543
I think 20% performance is a bit of a perfect world performance increase rather than real world especially...