4K - Batman: Arkham Origins
Batman: Arkham Origins features an expanded Gotham City and introduces an original prequel storyline occurring several years before the events of Batman: Arkham Asylum and Batman: Arkham City.
We've established the Radeon R9 285 architecture, ostensibly weaker on paper, is a good match for the Radeon R9 280 and generally beats the price-comparable GeForce GTX 760 in most titles at 1080p allied to lush image-quality settings.
What's yet to be determined is whether the smaller framebuffer - 2GB vs. 3GB - has any meaningful impact as the resolution is raised to 3,840x2,160 (4K).
A trio of games have been benchmarked again, at 4K, with antialiasing disabled to allow the GPUs to offer reasonable framerates. Fluctuating performance and stalls are a hallmark of framebuffer limitations, so let's watch out for those.
Sapphire's card is approximately five per cent faster than the regular R9 280 at 1080p. The gap increases to a massive 32 per cent at 4K. This seems counter intuitive at first glance, because surely the 3GB-equipped R9 280 should do better.
The fast-frame standard is reduced from 17ms to 33ms - these cards aren't going to be averaging close to 60fps at this resolution. The measurements inside the second don't lie. Radeon R9 285 is a better bet, albeit not quite so impressive when the 99th percentile frame time is taken into account.
One reasonable explanation for the R9 285 handing the R9 280 a beating has to do with the Tonga GPU's vastly greater tessellation/geometry ability, which reduces the need for bandwidth-sapping high-resolution models. The newer architecture does more with less.
Oh, and the game plays reasonably smoothly, as well.