The State of DirectX 11 - Image Quality & Performance

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The State of DX11

A few years ago, we discussed the state of DirectX 10 and came back unimpressed. Not only did the available games of the time perform poorly under DirectX 10 on available hardware, image quality gains were nearly non-existent. Switching from DirectX 9 to DirectX 10 dropped performance by half with almost no discernible image quality improvement. Most of the DirectX 10 image quality perks we spotted in the games we checked out were due to specific developer decisions and had little to do with the new API. Now, nearly three years later, we're sorting through yet another mountain of data for yet another new DirectX API iteration, the 11th in the series. Thankfully things are looking up this time around.

We've tested five of the earliest available DirectX 11 titles and we're happy to report that the situation this time around is looking quite favorable for early adopters. While we observed performance hits when switching to DirectX 11 from DirectX 9 in all five games, we also observed a noticeable corresponding image quality improvement. The drop in performance for DirectX 11 in our tests can be attributed to the added image quality. Effects like tessellation, screen-space ambient occlusion, advanced post processing and DX11 exclusive anti-aliasing in some games brought the performance down in our testing, but they also boosted image quality.

What's more, it would seem that some of the games actually performed noticeably better in DirectX 11, compared to DirectX 10 and 9, when the extra image quality features exclusive to DirectX 11 were not enabled, as we observed in Alien vs. Predator. This suggests that DirectX 11 rendering paths can be faster than their DirectX 9 counterparts while maintaining the same image quality level in some scenarios.

In terms of image quality, the new effects and graphical tricks we saw with DX11 added some extra realism not available in DirectX 9. Effects like screen-space ambient occlusion, depth of field, and tessellation really brought the graphics up a notch, adding extra atmosphere and realism to games like Aliens vs Predator, Bad Company 2 and Dirt 2. However, these effects were generally quite subtle and are nothing as dramatic as the image quality changes brought on by DirectX 8 or 9 in the past, which both offered major milestones in shader technology. It's also worth noting that, except for tessellation, these effects are all technically possible without DirectX 11 and compute shaders, as proven by Crysis.

DirectX 11's hardware tessellation and DirectCompute API have great potential, but currently they're being used to implement effects we've seen before since Crysis was introduced. While that certainly doesn't sound very impressive, keep in mind that although the graphical effects are nothing new, DirectCompute now makes them much more efficient. So efficient, that all five games were able to run at full HD resolution (1920x1200) with all the graphics setting cranked to max without much trouble, even on the affordable $150 Radeon 5770. This means that game developers will be much more willing and likely to implement these effects in their titles, so watch for them in the coming months. Overall, performance in currently available DirectX 11 games is excellent.

Is DirectX 11 Worth Your Time?
Ultimately DirectX 10 will be remembered as a stepping stone. It was a necessary evil that helped rid the DirectX API of over a decade of legacy dead weight. We predict it will be overshadowed in the memories of most gamers by DirectX 11 which looks like it will finally make much of the hype originally created for DirectX 10 a reality. Currently available DirectX 11 titles and hardware really delivers, both in terms of performance and image quality, though arguably not quite at the same time. If you've held out on Vista and DirectX 10, and have been waiting to see if something better comes along before leaving your beloved DirectX 9 WinXP gaming platform behind... well, it appears to be here and it's called DirectX 11.

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