Gigabyte Z87X-OC Review
CatZilla is so GPU bound that whether the i7 is at stock or heavily overclocked the scores don't vary much. As the image quality increases to realistic levels the gaps become negligible. Certainly the gaming result of PC Mark Vantage isn't replicated here.
Unigine Valley is nothing if not beautiful. Once again though we see that 3D testing is far more about the GPU that you have installed than any particular choice of motherboard. If you're mainly building a gaming rig then spend the money on a great graphics card rather than a stunning mobo.