Radeon RX 6800 XT vs GeForce RTX 3080 • Eurogamer.net

AMD’s new RDNA 2 architecture arrived for desktop PCs through the RX 6000 graphics card line – and is an important launch, bringing with it complete hardware support for the DirectX 12 Ultimate feature set, including the DXR API. Yes, ray tracing is now an integral part of AMD’s next-generation parts, and we wanted to get an idea of ​​how effective the Radeon version of technology is on the RX 6800 XT – and how it compares to its closest rival, the RTX 3080 The benchmarks showed that Nvidia’s second generation technology is faster than AMD’s debut offering, but what is the full story here?

To help assemble this part, XFX sent me an example of a factory overclocking of the RX 6800 XT, specifically the Speedster Merc 319 edition of the board. Using its own three-fan cooler design, this monstrous card offers clock impulses rated at 2340 MHz, about five percent higher than the reference model, but I have routinely seen watches in the 2400 MHz range and beyond. Although the XFX board 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 70 degree Celsius range under load. As I mentioned, however, it is somewhat bestial in terms of form factor. Certainly in terms of its overall size, you need to ensure that there is adequate space in your box – it is about 34 cm or 13.5 inches long!

In terms of actual ray tracing metrics, it’s best to refer to the video here for a complete analysis of how I tested individual RT effects and how they are handled in each of our competing GPU architectures, but the main purpose of this test was to isolate individual stages from the RT pipeline to see how Nvidia and AMD perform, and to do so within the context of three main RT effects: shadows, reflections and global lighting.

Typically, in any RT scenario, there are four steps. To begin with, the scene is prepared on the GPU, filled with all objects that can affect the radius trace. In the second stage, the rays are fired for that scene, passing through it and tested to see if they reach the objects. Then there’s the next step, where the results from step two are shaded – like the color of a reflection or whether a pixel is in or out of the shadow. The final step is to decrease the noise. See, the GPU cannot send an unlimited amount of rays to be tracked – only a finite amount can be tracked, so the end result looks very loud. Denoising softens the image and produces the final effect.

Therefore, there are several factors at play when dealing with RT performance. Of the four steps, only the second is hardware-accelerated – and the actual implementation between AMD and Nvidia is different, with GeForce cards having additional hardware. RDNA 2 calculates the transverse radius in computing units, introducing competition for resources, while Nvidia does this in a specialized processor within the RT core. The first configuration stage can have significant CPU requirements, while the shading and noise elimination 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 malfunction on AMD hardware (which Nvidia would not have access to when coding it), it was certainly designed to work at its best on RTX cards.

Regardless, in the video, I intend to be comprehensive in addressing the entire ray tracing pipeline across both architectures, covering a range of effects. Shadows with lightning tracking are tested in Call of Duty: Black Ops Cold War (a title sponsored by Nvidia), as well as in Dirt 5 (supported by AMD). I take a look at the ray-traced reflections in Ghostrunner in Unreal Engine 4, where I can examine the effect with some degree of adjustment and, of course, the Watch Dogs Legion reflections are also placed under the microscope. I chose this because the AMD RT hardware is used on the consoles to provide the effect, in addition to, through modding, I can access the console and Nvidia’s denoisers. With global lighting tracked by lightning, 4A Games’ incredible Metro Exodus is tested in depth, while I see a more extreme example through the tracked Quake 2 RTX – which now works on AMD and Nvidia RT hardware, thanks to the integration of the finished equipment Vulkan RT extensions.

So, what’s the lesson? I think there are some intriguing results here. Lightning tracking shadows are generally inexpensive on features in both the RX 6800 XT and RTX 3080 – with the RTX 3080 achieving minimal gains in lower settings, which increase as the quality of lightning tracking increases at higher settings, in a game like Call of Duty Black Ops. For ray-traced reflections, the effect is much more demanding on the GPU hardware, but the visual victory is more pronounced in many scenarios. The greater the randomness of the reflected rays and the greater the number of rays fired, the greater the result of the RTX 3080 compared to the RX 6800 XT, rendering in almost half the time in certain configurations. The RTX 3080’s efficiency advantage diminished after a certain tipping point, however, and I saw the same thing with global lighting: the RTX 3080 could render the effect in almost half the time on Metro Exodus, or even a third of the time on Quake 2 RTX, still increasing the amount of lightning after that saw the RTX 3080 having less of an advantage.

In general, from these tests, it appears that the simpler the ray tracing is, the more similar the rendering times for the effect will be between competing architectures. The Nvidia card is undoubtedly more capable across the RT pipeline, and the RTX 3080 appears to experience less dramatic performance losses as the complexity of lightning tracking increases, but at the less complex end of the scale, AMD is competitive. Meanwhile, Spider-Man: Miles Morales on PlayStation 5 demonstrates that the Radeon ray tracing can produce some impressive results in more challenging effects – and this using a GPU that is significantly less powerful than the 6800 XT. And with that in mind, we need to accept that ray tracing on the PC side is still in its early days, especially when running on AMD hardware. At the moment, I can only provide general conclusions from a representative, but still a small sample. So far, we’ve only seen RT shadows in AMD-sponsored titles, and I’m looking forward to seeing how future titles developed in collaboration with Team Red will fare in demanding RT effects. Although lightning tracking has been with us now in the PC space for more than two years, the story is just beginning – and I can’t wait to see what comes next.