There are a couple of ways to overclock your system using the Gigabyte Z97X-Gaming GT. The easiest way would be by using the EasyTune software. It has different overclocking settings depending on your processor. It also has an auto-tuning mode. I tried that out and what it seems to do is start auto-overclocking and running a stability test after each overclock. It took our Core i7-4790K up to 4.7 GHz before our system bluescreened. After restarting I was surprised that the auto-tuning software did not start back up. Our system stayed at the max stable overclock that was 4.6 GHz. This is actually quite good for auto-tuning software.
You can also use the EasyTune software to set your overclocking values without having to go into the BIOS.
Of course you can also go into the BIOS and easily set your overclocking values as well. Just like the auto-tune I was able to manually set the system to a stable overclock of 4.6 GHz.
If we compare that to the other motherboards we have tested with this processor you can see that it is on par with the ASUS Z97-A and the MSI Z97 MPower as far as overclocking potential.