Watch AMD's DirectX Raytracing Demo on Future RDNA 2 GPU

By Niels Broekhuijsen
published

Mirror mirror on the wall...

(Image credit: AMD)

It's the moment we've all been waiting for: Nvidia has been the exclusive maker of hardware-accelerated ray tracing graphics, and we've all been waiting for AMD to join the party. That's not quite happening today, but with Microsoft's Xbox Series X and Sony's PlayStation 5 supporting the technology on RDNA 2 hardware, it's only a matter of time before we start seeing RDNA 2 hardware for PCs. In light of that, AMD released a one minute tech demo of what this may look like on its upcoming graphics architecture.

The demo is made possible by the new DirectX 12 Ultimate API, which, among other features, adds support for DirectX Raytracing 1.1 in the DXR API. Currently only Nvidia's GPUs support the API, but that will change when AMD's RDNA 2 graphics cards land in the consumer market. 

Say of the demo what you will. We don't think it's the kind of art that we'd like to see in a game, because frankly... Mirror mirror on the wall...

However, the sheer abundance of mirrors, glass, polished metals, and other reflective surfaces do make for a very demanding tech demo. As developers, you can optimize all you want, but having that many reflective surfaces in a scene and smoothly running raytracing on it is an accomplishment to be proud of.

The demo does appear to run slightly choppy, though. We downloaded the video and slowly clicked through it, counting a framerate of around 26 FPS, with most frames (on the 1080p60 file) being repeated two or three times, sometimes more. That explains the stutter, but we're not sure whether it's because of the demo being very complex (AMD provided a lengthy list of all the ray tracing graphics effects being used), or if the hardware is running slower than we'll see in final GPUs, or perhaps YouTube is throttling image quality to preserve internet bandwidth during the current Coronavirus outbreak.

One thing we have learned from Nvidia's attempts to promote ray tracing over the past 18 months: It's very hard to come up with a 'must have' use case for the technology that doesn't tank performance on lesser GPUs.

We're excited to see what the next-generation of graphics hardware has in store for us with regards to raytracing. Hopefully, it will meet the expectations that were set two years ago, not only in graphical fidelity, but also in terms of performance.

Niels Broekhuijsen
Niels Broekhuijsen

Niels Broekhuijsen is a Contributing Writer for Tom's Hardware US. He reviews cases, water cooling and pc builds.

29 Comments Comment from the forums
  • tiggers97
    What is the bandwidth requirements for something like this to run smoothly? (i.e. PCIe 4.0 suddenly making sense?)
    Reply
  • alextheblue
    One thing we have learned from Nvidia's attempts to promote ray tracing over the past 18 months: It's very hard to come up with a 'must have' use case for the technology that doesn't tank performance on lesser GPUs.
    Bingo. We'll see how it goes, but really anything below 2080 level right now takes a serious beating if you have a title that uses RT heavily. Hoping next-gen brings at least that level of RT performance down to the mid-tier cards.
    Reply
  • cryoburner
    Mirrors... Mirrors everywhere... I kind of think the demo would have had more of an impact had they started it in a room with limited reflective surfaces, instead focusing on effects like raytraced global illumination and shadows, before heading outside into mirror-land. And maybe reduce the number of mirrors out there a bit. It was kind of hard to tell if other raytraced effects were getting utilized with practically everything given a mirror-finish. Or maybe that was point. It's possible that each company's raytracing hardware might handle certain effects better than the other's, and they may be trying to showcase something that might not run as well on Nvidia's hardware.

    tiggers97 said:
    What is the bandwidth requirements for something like this to run smoothly? (i.e. PCIe 4.0 suddenly making sense?)
    I doubt it. If anything, the reduced framerates when raytracing will likely reduce demand over the PCIe bus, unless perhaps AMD is doing something like offloading a major part of the raytracing workload to the CPU, and transferring a lot of additional data in the process. Indications are that graphics cards are not coming close to the performance limitations of a PCIe 3.0 x16 slot though, and probably won't be for some years to come.
    Reply
  • Chung Leong
    cryoburner said:
    It was kind of hard to tell if other raytraced effects were getting utilized with practically everything given a mirror-finish. Or maybe that was point. It's possible that each company's raytracing hardware might handle certain effects better than the other's, and they may be trying to showcase something that might not run as well on Nvidia's hardware.

    Perfectly reflective surfaces aren't hugely taxing actually. One ray in, one ray out. When a ray spawns multiple secondary rays upon hit a surface that's when it gets hard. If the hardware is only capable of doing what's shown in this demo, then it's decidedly inferior to RTX.
    Reply
  • Makaveli
    tiggers97 said:
    What is the bandwidth requirements for something like this to run smoothly? (i.e. PCIe 4.0 suddenly making sense?)

    The words you are looking for is Raytracing in hardware.

    I seriously doubt bandwidth is an issue here.
    Reply
  • cryoburner
    Chung Leong said:
    If the hardware is only capable of doing what's shown in this demo, then it's decidedly inferior to RTX.
    Well, I'm pretty sure it will be capable of more than that. Microsoft has already been talking about how DXR will be offering "improved lighting, shadows and reflections as well as more realistic acoustics and spatial audio" on the new Xbox, so AMD's raytracing implementation should be more or less feature complete with Nvidia's, from the sound of it. The question comes down to performance though, as we have no real indication of how any of this hardware will perform compared to the first-gen RTX cards. It could be substantially faster, for all we know, but there's no way of telling until side-by-side comparisons can be made. And the same goes for the next generation of RTX cards. We'll likely know more later in the year.

    And of course, this demo doesn't seem to have been done by a big game developer or anything. The art and animations in general have a somewhat budget, tech-demo feel to them, even compared to something like the recent 3DMark demos, so things will likely look a lot more impressive in the hands of skilled developers with larger budgets to work with.
    Reply
  • Chung Leong
    cryoburner said:
    The question comes down to performance though, as we have no real indication of how any of this hardware will perform compared to the first-gen RTX cards. It could be substantially faster, for all we know, but there's no way of telling until side-by-side comparisons can be made.

    Given the pressure on price, it wouldn't be unreasonable for Microsoft to support just the obvious and forego the more subtle. Puddles! Woohoo!
    Reply
  • hannibal
    These are still early stage raytrasing. In few years we will get GPU that are fast enough... Next gen Ampera is not yet fast enough. Neither these consoles. Too early for that. A couple of years more raytrasing is needed.
    Reply
  • digitalgriffin
    admin said:
    It oozes raytracing. Oh such satisfying raytracing.

    Watch AMD's DirectX Raytracing Demo on Future RDNA 2 GPU : Read more

    It was a good demo and technically superior to NVIDIA's Star Wars demo.

    HOWEVER it wasn't as neat, subtle, or balanced in it's presentation.

    The objective of ray tracing is NOT to show horsepower with everything being a mirror, but to make things more realistic with caustics, shadows, ambients, refraction, and some reflective surfaces.
    Reply
  • Chung Leong
    digitalgriffin said:
    It was a good demo and technically superior to NVIDIA's Star Wars demo.

    The Nvidia's Star Wars demo was close to photorealistic. This demo, meanwhile, proves the assertion that ray-tracing with primary rays alone is practically rendering.
    Reply