Overclocking on the Z97X-UD3H-BK can be done a few different ways. First there are set overclocks in the Gigabyte EasyTune software depending on your processor. For our Core i7-4790K there are overclocks all the way up to 4.7 GHz.
There is also an auto tuning feature that will test overclocks until it find the best one.
You can also just go into the BIOS yourself and change settings around. After changing a few settings around the max stable overclock I was able to achieve was 4.6 GHz at 1.40v. The system did boot at 4.7 GHz, but did not pass all of our benchmark tests.