AMD’s all-new RDNA 2 architecture has arrived for desktop PCs via the RX 6000 line of graphics cards – and it’s a significant release, bringing with it full hardware support for the DirectX 12 feature set. Ultimate, including the DXR API. Yes, ray tracing is now an integral part of AMD’s high-end parts, and we wanted to get a feel for how effective the Radeon rendering of the technology was in the RX 6800 XT – and how it compares to its closest rival. , the RTX 3080. Benchmarks have shown that Nvidia’s second-generation technology is faster than AMD’s initial offering, but what’s the full story here?
To help put this part together, XFX sent me a factory overclocked example of the RX 6800 XT, specifically the Speedster Merc 319 edition of the board. Using its own three-fan cooler design, this monstrous board delivers boost clocks rated at 2340 MHz, about five percent more than the benchmark model, but I’ve seen it regularly hit clocks in the 2400 MHz range. and beyond. While the XFX card has a new brand, the design philosophy has a lot in common with its previous “THICC” line. The cooler is certainly similar and does a good job of keeping temperatures in the low 70s Celsius range under load. As I mentioned though, it’s a bit bestial in terms of form factor. Granted, in terms of volume, you need to make sure you have adequate clearance in your case – it measures around 34cm or 13.5 inches in length!
As for ray tracing metrics, it’s best to refer to the video here for a full description of how I tested the individual RT effects and how they are handled on each of our architectures. GPUs competing, but the primary focus of these tests was to isolate individual stages of the RT pipeline to see how Nvidia and AMD perform, and to do so in the context of three key RT effects: shadows, reflections, and lighting. global.
Thanks to XFX for sending Alex the RX 6800 XT Speedster Merc 319 render of the card that made this content possible.
Typically, in any RT scenario, there are four stages. To begin with, the stage is set up on the GPU, filled with all the objects that could potentially affect ray tracing. In the second stage, the rays are projected into this scene, passing through it and tested to see if they hit objects. Then there is the next step, where the results of the second step are shaded – like the color of a reflection or whether a pixel is in or out of the shadow. The last step is denoising. You see, the GPU cannot send unlimited amounts of rays to be traced – only a finite amount can be traced, so the end result looks quite noisy. Denoising softens the image and produces the final effect.
Thus, there are many factors that go into the processing of RT performance. Of the four stages, only the second is hardware accelerated – and the actual implementation between AMD and Nvidia is different, with GeForce cards having an additional hardware grunt. RDNA 2 calculates ray traversal on the compute units, introducing competition for resources, while Nvidia does this in a dedicated processor within the RT core. The first configuration step may have significant processor requirements, while the shading and noise reduction steps may have specific preferences for certain GPU architectures. For example, Quake 2 RTX and Watch Dogs Legion use a denoiser built by Nvidia and although it was not designed to perform poorly on AMD hardware (which Nvidia would not have had access to when they coded it) , it is certainly designed to perform as well as possible on RTX cards.
Anyway, in the video I aim to be complete by tackling the entire ray tracing pipeline across both architectures, covering a range of effects. Ray-traced shadows are tested in Call of Duty: Black Ops Cold War (an Nvidia sponsored title) as well as Dirt 5 (supported by AMD). I watch ray traced reflections in Ghostrunner in Unreal Engine 4, where I can examine the effect with some degree of tuning, and of course the reflections in Watch Dogs Legion are put under a microscope as well. I chose this one because AMD RT hardware is used in the consoles to provide the effect, and through modding I can access both the console and Nvidia denoisers. With ray-traced global illumination, 4A Games’ amazing Metro Exodus is tested in depth, while I look at a more extreme example via the Quake 2 RTX pathway – which now works on AMD and Nvidia RT hardware. , thanks to the integration of finalized Extensions Vulkan RT.
The Digital Foundry review of BIG NAVI cards, and how they compare in more general terms to their Nvidia counterparts.
So what’s the takeaway? I think there are some interesting results here. Ray-traced shadows are generally inexpensive in resources on the RX 6800 XT and RTX 3080 – with the RTX 3080 seeing minimal gains at lower settings, which then increase as the quality of ray-tracing is increased at lower settings. higher settings, in a game like Call of Duty Covert Ops. For ray traced reflections, the effect is much more demanding on GPU hardware, but the visual victory is more pronounced in many scenarios. The higher the randomness of the reflected rays and the greater the amount of projected rays, the better the RTX 3080 fares compared to the RX 6800 XT – almost half the time in some configurations. The efficiency benefit of the RTX 3080 waned after a certain tipping point, however, and I saw the same with global lighting: the RTX 3080 could render the effect almost half the time in Metro. Exodus, even a third of the time in Quake 2 RTX, but increasing the amount of rays after that saw the RTX 3080 have less advantage.
In general, based on these tests, it appears that the simpler the ray tracing, the more similar the effect render times between competing architectures. The Nvidia card undoubtedly performs better across the entire RT pipeline, and the RTX 3080 appears to have less dramatic performance losses as the complexity of ray tracing increases, but at the less complex end of the line. ‘scale, AMD is competitive. Meanwhile, Spider-Man: Miles Morales on PlayStation 5 demonstrates that Radeon ray tracing can produce impressive results on more difficult effects – and that uses a significantly less powerful GPU than the 6800 XT. And with that in mind, we have to accept that PC-side ray tracing is still in its infancy, especially when run on AMD hardware. At the moment, I can only deliver general conclusions from one representative, but still a small sample. So far we’ve only seen RT shadows in AMD-sponsored titles, and I can’t wait to see how future titles have developed together with Team Red for demanding RT effects. With ray tracing with us now in the PC space for over two years, the story has only just begun – and I can’t wait to see what comes next.
Article source https://www.eurogamer.net/articles/digitalfoundry-2021-pc-ray-tracing-deep-dive-rx-6800xt-vs-rtx-3080