4 ms·

> They are presumably not going to be able to match NVIDIA’s energy efficiency, and they won’t have feature parity since AMD doesn’t (yet) have its own DirectX

> They are presumably not going to be able to match NVIDIA’s energy efficiency, and they won’t have feature parity since AMD doesn’t (yet) have its own DirectX Raytracing (DXR) implementation. I assume this means that it won't support raytracing at all? Or will it, but with some non-DXR implementation?

pitaj 8y ago
They might support it with a software upgrade in the future, but I doubt it.
dragontamer 8y ago
NVidia's raytracing is hardware accelerated. There's specific cores that can ONLY traverse a BVH tree built into the NVidia hardware. Furthermore, NVidia's raytracing features leverage FP16 matrix multiplication for denoising. The Radeon VII will certainly be slower at raytracing (if AMD ever decides to support the feature). It has FP16 support and huge RAM bandwidth (which will help traverse a BVH Tree), but I would expect it to be many times slower than dedicated hardware units. Without tensor cores (VII only supports hardware-accelerated FP16 Dot-products), there's no way it'd keep up with Nvidia on denoising or BVH traversals.
- CoolGuySteve 8y ago
  Based on the pixel sparkling in the video I've seen if Battlefield, it looks like Nvidia's raytracing is being used for each pixel. I'm not sure if it has to be that way or if it's just underoptomozed at the moment. I think you could get something 95% as good with far better performance by only tracing vertices and then raster rendering the resultant transform. Would be a good approach for accurate shadows too where you don't really care about texture fragments.
  - dragontamer 8y ago
    > Based on the pixel sparkling in the video I've seen if Battlefield, it looks like Nvidia's raytracing is being used for each pixel. I'm not sure if it has to be that way or if it's just underoptomozed at the moment. 1-sample per pixel is already incredibly low for raytracing. A raw 1 spp raytraced image looks HORRIBLE. The reason why it looks anywhere close to usable is because NVidia post-processes all of that noise through their tensor-cores FP16. It is some kind of spacial / temporal-filter effect (averaging pixels across time, and space... where "space" is mapped to geometry framebuffers to keep object boundaries correct).
    - CoolGuySteve 8y ago
      Ya that's kind of what I'm getting at. If your physically accurate rendering is pushing the hardware limits so far that you need extensive post processing to maintain the framerate then it stops being so physically accurate. At that point, it seems like there are more interesting things you can do with the hardware than a naive raytrace that would look and perform better while, admittedly, not being 100% physically accurate.
      - lostmyoldone 8y ago
        I'd be very surprised if most common usage of RTX would turn out to be anything even remotely physically accurate. A more likely use in the immediate future is to simplify some parts of the rendering pipeline, and improve quality on a few others. Without looking too much into to it, improving and simplifying soft shadows and are lighting seems like a no-brainer. Both are really hard to implement efficiently using rasterization, and/but both needs a good denoiser. Will be interesting to see thought. I believe it's a bit later than I predicted that we get to see real time ray tracing on commodity hardware, but what is a couple of years over a few decades?
    - posterboy 8y ago
      If I understand you correctly, they mix rays coming from one spot over many frames instead of shooting more rays in a single frame? That sounds great and a bit inspired by natural vision. Optical flow sensors are cheap enough for computer mouses and the like. But who says it's really just one ray? The number of frames to integrate would be too high Of course that'd work for fps as slow as battle of duty \s
ABeeSea 8y ago
It likely won’t without ray tracing specific hardware. Theoretically, they don’t need the hardware and can use the directx ray tracing api and do software acceleration. It will just run very very slowly. https://www.anandtech.com/show/12547/expanding-directx-12-microsoft-announces-directx-raytracing https://www.anandtech.com/show/12547/expanding-directx-12-mi...

pitaj 8y ago

They might support it with a software upgrade in the future, but I doubt it.

dragontamer 8y ago

NVidia's raytracing is hardware accelerated. There's specific cores that can ONLY traverse a BVH tree built into the NVidia hardware. Furthermore, NVidia's raytracing features leverage FP16 matrix multiplication for denoising. The Radeon VII will certainly be slower at raytracing (if AMD ever decides to support the feature). It has FP16 support and huge RAM bandwidth (which will help traverse a BVH Tree), but I would expect it to be many times slower than dedicated hardware units. Without tensor cores (VII only supports hardware-accelerated FP16 Dot-products), there's no way it'd keep up with Nvidia on denoising or BVH traversals.

CoolGuySteve 8y ago
Based on the pixel sparkling in the video I've seen if Battlefield, it looks like Nvidia's raytracing is being used for each pixel. I'm not sure if it has to be that way or if it's just underoptomozed at the moment. I think you could get something 95% as good with far better performance by only tracing vertices and then raster rendering the resultant transform. Would be a good approach for accurate shadows too where you don't really care about texture fragments.
- dragontamer 8y ago
  > Based on the pixel sparkling in the video I've seen if Battlefield, it looks like Nvidia's raytracing is being used for each pixel. I'm not sure if it has to be that way or if it's just underoptomozed at the moment. 1-sample per pixel is already incredibly low for raytracing. A raw 1 spp raytraced image looks HORRIBLE. The reason why it looks anywhere close to usable is because NVidia post-processes all of that noise through their tensor-cores FP16. It is some kind of spacial / temporal-filter effect (averaging pixels across time, and space... where "space" is mapped to geometry framebuffers to keep object boundaries correct).
  - CoolGuySteve 8y ago
    Ya that's kind of what I'm getting at. If your physically accurate rendering is pushing the hardware limits so far that you need extensive post processing to maintain the framerate then it stops being so physically accurate. At that point, it seems like there are more interesting things you can do with the hardware than a naive raytrace that would look and perform better while, admittedly, not being 100% physically accurate.
    - lostmyoldone 8y ago
      I'd be very surprised if most common usage of RTX would turn out to be anything even remotely physically accurate. A more likely use in the immediate future is to simplify some parts of the rendering pipeline, and improve quality on a few others. Without looking too much into to it, improving and simplifying soft shadows and are lighting seems like a no-brainer. Both are really hard to implement efficiently using rasterization, and/but both needs a good denoiser. Will be interesting to see thought. I believe it's a bit later than I predicted that we get to see real time ray tracing on commodity hardware, but what is a couple of years over a few decades?
  - posterboy 8y ago
    If I understand you correctly, they mix rays coming from one spot over many frames instead of shooting more rays in a single frame? That sounds great and a bit inspired by natural vision. Optical flow sensors are cheap enough for computer mouses and the like. But who says it's really just one ray? The number of frames to integrate would be too high Of course that'd work for fps as slow as battle of duty \s

ABeeSea 8y ago

It likely won’t without ray tracing specific hardware. Theoretically, they don’t need the hardware and can use the directx ray tracing api and do software acceleration. It will just run very very slowly. https://www.anandtech.com/show/12547/expanding-directx-12-microsoft-announces-directx-raytracing https://www.anandtech.com/show/12547/expanding-directx-12-mi...