At 24% faster than the GTX 1080 SLI combo, 1080 Ti SLI blasts through this demanding game at 4K. But as with previous results, scaling is a little bit off the mark, dropping below 60% with 1080 Ti SLI, whereas it was above 70% for the weaker 1070 SLI combo. Evidence of a failure of SLI? Not at all, folks, though some may like to read the results that way to fend off an impulse buy!
A funny thing happened while we were benching Fallout 4 for this article: we found framerates to go sky high, far higher than we'd ever seen before. Well, it turns out it wasn't due to the magic of the 1080 Ti SLI combo, but rather the fact that our in-game benchmark had been played enough times that the scene switched over to night (Fallout 4 has dynamic day/night cycles). Since we don't use canned benchmarks, we're subject to the vagaries of real-world testing, and that meant we couldn't include our results on the GTX 1070 and GTX 1080, which we'd collected previously when our game was still in the daytime mode, where the lighting model is far more complex (think tons of ambient occlusion to drain GPU power!).
Alas, with the high framerates we were hitting without daytime lighting in effect, SLI was significantly hampered in stretching its legs. There just wasn't enough for the dynamic duo of GTX 1080 Ti GPUs to do. Scaling was around 50%. Of course, that was still good enough to hit the highest framerates of any of our benchmarks, and honestly speaking, absurdly fast for 4K monitors, which are currently limited to 60Hz.
Rise of the Tomb Raider
Rise of the Tomb Raider is traditionally viewed as completely GPU-limited, and we've found it to be a fantastic test of GPU power in the past. But oh boy, things are starting to look rough for GTX 1080 Ti SLI. Here it's just 10% faster than the 1080 SLI setup, and the 10% overclock only provided an extra 4% boost. This is a CPU limitation, plain and simple, and we're going to come back to this result later on, as it really provides a significant insight into what's going on with SLI with currently-available CPUs.