I love it when people rush out and buy the reference cards and say reference is the same as the aftermarket custom cooler cards. And then they aren't. That's okay, someone has to drive the initial demand until the customs start shipping out since they are usually delayed by a few weeks to a month after reference card launch occurs.
The people who say EVGA is as good as or better than MSI, ASUS, Gigabyte, Zotac, etc. can keep believing it too. Lifetime warranty sounds nice until you realize the average video card's useful lifespan is much shorter than a lifetime. Then all of a sudden the Gigabyte 3 year warranty doesn't sound bad at all, it's longer than most video cards will be useful for already. Meanwhile MSI, ASUS, Gigabyte, Zotac, etc. are using custom PCB designs with superior quality components over reference and also in the case of 980 Ti, they are using 2x 8-pin PCIe power connectors instead of the 6-pin + 8-pin layout the reference boards use which gives you more headroom for over-voltage and therefore higher OCs.
There's no wizardry involved with the Gigabyte G1 SOC getting those OCs, it's common for the AIB manufacturers to cherry pick their best samples to send out to reviewers. As always with factory OCed video cards, YMMV from review sample to the actual production card that you buy.