AoTS was an early flag-bearer for DirectX 12, and the performance gains AoTS offers in DX12 over DX11 are mind-blowing—at least for AMD cards. AoTS’s DX12 implementation makes heavy use of asynchronous compute features, which are supported by dedicated hardware in Radeon GPUs, but not GTX 900-series Nvidia cards. In fact, the software pre-emption workaround that Maxwell-based Nvidia cards use to mimic the async compute capabilities tank performance so hard that Oxide’s game is coded to ignore async compute when it detects a GeForce GPU.
That creates some interesting takeaways in performance benchmarks. Maxwell-based Nvidia GPUs actually perform worse in DirectX 12 mode, while AMD’s Radeon cards see massive performance gains with DX12 enabled—to the point that the Fury X in DX12 is able to essentially equal and sometimes even outpunch the reference GTX 1080’s baseline DX11 results, even though the GTX 1080 clobbers the Fury X’s DX11 results. That’s a big win for AMD.
That said, once you take the pedal off the metal and look at results below 4K/crazy, the GTX 1080 starts to see decent performance increases in DX11 vs DX12 performance, though it never nears the mammoth leaps that Radeon graphics cards enjoy. At 1440p/high settings, shifting to DirectX 12 gives the GTX 1080 a 20.3-percent performance leap. Therefore, even though AoTS explicitly disables basic async compute in Nvidia cards, the new async compute enhancements Nvidia’s built into Pascal can indeed provide tangible benefits in DX12 games with heavy async compute utilization.
Looking directly at Nvidia-to-Nvidia performance, the GTX 1080 provides frame rate increases similar to what we’ve seen in other games: Roughly 72 percent more performance than the GTX 980, and 35 to 40 percent over the Titan X.
SteamVR benchmark and virtual reality
The biggest bummer for me in this review is that VR benchmarks haven’t been able to keep up with graphics technology.
Nvidia’s biggest claim to performance fame with the GTX 1080 lies in virtual reality. While the traditional performance games are sizeable enough, Nvidia’s loftiest performance claims—faster than two GTX 980s in SLI! 2.7x performance increases!—are firmly tied to VR games that make full use of Nvidia software like simultaneous multi-projection. Unfortunately, the granular VR benchmark tools coming from Crytek and Basemark haven’t hit the streets, and no released VR games support the GTX 1080’s new software features yet. That leaves us with no way to quantify the GTX 1080’s potential performance increase over the competition except for the SteamVR benchmark, which is better for determining whether your rig is capable of VR than direct head-to-head GPU comparisons.
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