SLI scaling in this game is terrible, and in past articles, we've made known the fact that if DOOM is your game of choice, you simply should not upgrade to SLI exclusively to run it. Offering up a weak 28% boost over a single GPU at reference clocks, or a 21% boost once overclocked, this is the worst result of the roundup.
As an aside, we've found that the OpenGL renderer we used for this testing really doesn't cope well with CPUs offering more than four cores, so our eight-core 6900K isn't much of a benefit in this benchmark.
If you're a competitive BF1 gamer looking to sink some money into a high-end system to prepare for high-refresh rate 4K monitors coming later this year, GTX 1080 Ti SLI performance will likely bring a smile to your face. While one 1080 Ti is plenty to max out any current 4K monitor, two gets you up near the 120Hz mark, where you can really achieve gaming bliss, especially when running G-Sync on those dreamy 4K 144Hz monitors that both Acer and Asus have promised to deliver. That being said, we're still nowhere near 100% scaling here, as our overclocked duo hits just 50% in that regard.
Updated after we conducted testing on our 1070 and 1080 setups, Watch_Dogs 2 proves why it's always difficult to use a new game for benchmarking purposes. Our 1080 Ti cards were tested with the latest game patch, while the other cards used an earlier build, so the results aren't directly comparable - the 1080 Ti has the advantage of game engine improvements. That being said, this game is still surprisngly demanding at 4K, generating the lowest framerates in our testing. Given that the 4K results for a single 1080 Ti are well below 60fps, this is a game that SLI really makes sense for, despite only modest scaling.