We get the feeling that Nvidia's engineers had their hands on a couple of third-party Radeon RX Vega 56 cards when they launched GeForce GTX 1070 Ti. At the very least, they had some inside information. Sure, the 1070 Ti wasn't really meant to be much faster, avoiding cannibalization of GeForce GTX 1080. But Nvidia's card matches up quite well with the various factory-overclocked Vega 56 boards we've already benchmarked.
Results: 2560x1440 (QHD)
First, we test at 2560x1440, where a card like this is most likely to excel.
In practice, the Radeon RX Vega 56 Gaming OC 8G achieves a 9- to 11%-higher clock rate than AMD's reference card, resulting in average frame rates that are anywhere from 6- to 8% better. That's respectable scaling, to be sure.
Results: 3840x2160 (UHD)
The overall picture doesn't change much at 3840x2160, though there isn't much difference between Gigabyte's card and AMD's reference design. Neither option is ideal for 4K gaming with maxed-out settings. Compromises must be made on the detail sliders to bring frame rates up enough for smooth performance.
It's hardly possible to match these cards more perfectly. Sometimes the Radeon RX Vega 56 Gaming OC 8G is a bit faster than a GeForce GTX 1070 Ti, and sometimes it's the other way around. Overall, then, it can be hard to tell them apart. Too bad Nvidia seems to have boards for sale, while none of AMD's partners can say the same. An overclocked Radeon RX Vega 56 is quite fast by any standard.
MORE: Best Graphics Cards
MORE: All Graphics Content