OCC has published a review on the Gigabyte GA-Z77X-UD5H-WiFi

Now when it came to overclocking, the Gigabyte Z77X-UD5H-WiFi will allow your processor and memory to scale almost effortlessly when manually tweaking the settings. Up to the limits of your hardware at least. I was able to pull a 1.2GHz overclock out of the CPU and run the 2133MHz rated memory at up to 2400MHz by adjusting the timings and tweaking the voltages a bit for stability. Manually tuning in the 3D BIOS is not the only avenue to increase the performance of your installed hardware. Using Easy Tune 6 you can overclock from within the operating system to see what works and what does not. The utility does not come by the Easy Tune name just the sake of calling it something. Using the Auto Tuning feature of the Tuner section of ET6 you can choose a few preset options to overclock your hardware from a mild 4.18GHz using a 102MHz bclock to a more aggressive 4.68GHz using a 104MHz bclock.

  Gigabyte GA-Z77X-UD5H-WiFi Review