Radeon RX 6800 and 6800 XT ray tracing performance
Now let’s dig a bit deeper into the newfound real-time ray tracing capabilities of AMD’s graphics cards.
RDNA 2 marks the debut of ray tracing capabilities in Radeon graphics chips. Nvidia first introduced the technology in the GeForce RTX 20-series, and is now on its second-generation effort with the RTX 30-series. As you’d expect, Nvidia’s more mature technology delivers more performance, but how much more performance? We decided give Watch Dogs: Legion, Metro: Exodus and Shadow of the Tomb Raider a whirl to put it to the test. Hopefully we’ll be able to revisit the topic with a wider selection of games later—the gorgeous Godfall didn’t include ray tracing at launch, alas—but for now, this trio of games represents a decent selection of various ray tracing effects. Legion packs ray-traced reflections, Tomb Raider includes ray-traced shadows, and Metro features more strenuous (and mood-enhancing) ray-traced global illumination.
Complicating things further is DLSS. Nvidia’s Deep Learning Super Sampling feature renders games at a lower resolution, then taps into dedicated tensor cores that use AI to upscale the final image to your resolution. Because the game is being rendered at lower resolution, your graphics card’s traditional shading hardware can pump out frames faster, while DLSS’s AI delivers shockingly good final quality. Well, now at least. DLSS 1.0 suffered from some birthing pains, as covered in our RTX 20-series ray tracing retrospective, but the new DLSS 2.0 algorithms work beautifully.
Bottom line, though? DLSS is a key Nvidia advantage right now, especially if you’re interested in playing games with ray tracing active. AMD targeted playable 1440p performance with ray tracing enabled on the Radeon RX 6800-series and largely hit those goals, but DLSS helps Nvidia’s cards hit much higher frame rates, and even lets you play ray-traced games at 4K. AMD can’t match that. The company has teased a “FidelityFX Super Resolution” feature that it hopes will rival DLSS and gain more traction given RDNA 2’s inclusion in the next-gen consoles, but it’s not here yet.
It’s also worth noting that since the Khronos group’s ray tracing support for Vulkan hasn’t been officially released yet, any Vulkan games that currently support the technology were built using Nvidia extensions as a band-aid in the interim. That means you can’t enable ray tracing in Wolfenstein: Youngblood, Quake II RTX, or the Asian title JX3 on the Radeon GPUs, at least for now. The option doesn’t even appear in Youngblood. All other ray-traced games were built using Microsoft’s DirectX Raytracing API, however, so they should work just fine on both GeForce and Radeon hardware. Yes, that includes Cyberpunk 2077.
We’ve included three charts for each game—one for each major resolution. We split the results into several charts because we wanted to show native performance, performance with only ray tracing on, and performance with ray tracing and DLSS on (for Nvidia cards) at each resolution to get a more complete picture of things. We set ray tracing to ultra for all titles; using lower settings will have less of an impact.
Let’s kick things off with Shadow of the Tomb Raider’s ray-traced shadows. The game includes the first-generation version of DLSS and doesn’t support 1080p resolution, so we’ve stuck to raw ray tracing performance.
Flipping on ray tracing creates a big performance impact, as you’d expect, but it’s bigger on Radeon GPUs. As you can see, even though the AMD cards perform faster than their GeForce rivals with ray tracing off, they have slower performance with ray tracing on. Ray tracing slows the Radeon RX 6800 XT down by 41 percent at 1440p, and the Radeon RX 6800 by 46 percent. By contrast, Nvidia’s RTX 3070 slows down 37 percent with ray tracing active, and the RTX 3080 slows down only 28 percent.
The Radeon RX 6800 and 6800 XT exceed the hallowed 60-fps mark at 1440p resolution and clear 90 fps at 1080p. Flipping on DLSS gives Nvidia a massive performance lead, however, and it delivers enough extra oomph to let you play the game at 4K resolution on GeForce hardware. You won’t be able to do that with the Radeon RX 6800-series unless you dial back some visual settings.
Metro: Exodus uses ray tracing for global illumination. It also uses DLSS 1.0 and doesn’t support the upscaling feature at 1080p, so we’ve included only raw ray tracing performance on that chart.
Ray tracing reduces the performance on both Radeon RX 6800-series cards by 45 percent at 1440p. The RTX 3080 only loses 28 percent off the top, while the RTX 3070 loses 30 percent. Flipping on DLSS once again extends Nvidia’s lead. That said, the Radeon GPUs indeed achieve playable frame rates at 1440p and 1080p, though you will need to tinker with some visual settings to hit 60 fps at 1440p. GeForce cards can leverage DLSS to play with ray tracing on at all resolutions, though you’ll also need to tweak some things to get them running at 60 fps at 4K.
Watch Dogs: Legion hammers your system regardless of whether you have ray tracing on. None of these cards sustain 60 fps at 4K resolution even with the cutting-edge lighting effects turned off, at least with the high-resolution texture pack installed. Activating the ray-traced reflections exacerbates the issue. Unlike Tomb Raider and Metro, Watch Dogs uses the faster, better DLSS 2.0 technology. We test it with DLSS Balanced mode active. Balanced lets you hit higher frame rates than the Quality mode, but the even faster Performance mode starts to introduce visual differences you can notice in some scenes. Balanced hits the sweet spot.
The Radeon RX 6800 XT is 40 percent slower with ray tracing on at 1440p resolution, while the Radeon RX 6800 is 38 percent slower. By contrast, the RTX 3080 is 37 percent slower, while the RTX 3070 is 45 percent slower.
Interestingly, the Radeon GPUs suffer a bit less of a performance penalty than they do in the other games, while the GeForce cards get hit a bit harder. This game uses large amounts of memory, surpassing the RTX 3070’s 8GB capacity even at 1440p with ray tracing off. Turning it on increases the demands further. The beefier 16GB of memory on AMD’s cards help give them an edge here, letting the Radeon RX 6800 XT match the RTX 3080’s performance with ray tracing on at 1440p, while the RX 6800 is 18 percent faster than the RTX 3070.
That lead disappears once you flip on DLSS, of course, but it’s an encouraging sign for AMD’s design decisions. The RTX 3080 cannot hit 60 fps at 4K resolution even with DLSS enabled, and the 3070 can’t achieve 40 fps. AMD’s cards once again deliver playable frame rates at 1440p and 1080p, though they can’t quite hit 60 fps with all the visual bells and whistles cranked at 1440p. That’s more acceptable in an open-world third-person game like Legion, but you should easily be able to get to 60 fps by tinkering with various visual options.
All in all, the Radeon RX 6800-series GPUs deliver solid ray tracing performance at the most commonly played resolutions, 1440p and 1080p. Nvidia’s second-gen implementation has a performance advantage, and DLSS extends it even further. Ray tracing hits memory hard, though, and the larger VRAM capacity in the Radeon GPUs might be an advantage for them in future titles, like it is in Watch Dogs currently.
Next page: Power, thermals, and noise