Well it means the RT cores have not really been improved much at all but the performance increase is coming from the huge increase in CUDA cores.
The RT cores are bigger and more powerful. Its the reason why the number has not gone up a great deal from turning. AMD lag behind because they believe that RT should be very limited in games. More or less to lighing and the rest done in the cloud. DLSS was the feature that rocked this ideology. So they produced a card were the RT performance is secondary to rasterization, (AMD games have very little performance hit when RT is enable bucause there is very little of it).
People cry about the quality of DLSS is not the same as native rendering but ignore Variable Rate Shading in DX12u. A feature which allows a GPU to effectively render different parts of the scene at a different resolution, so the GPU can work more on areas that matter and less on areas that don’t.
You can see it here, https://www.tomshardware.com/uk/news/amd-patents-hybrid-ray-tracing-solution,39761.html AMD Files Patent for Hybrid Ray Tracing Solution
Nvidia went for a full RT solution with dedicated RT cores. DLSS which runs on dedicated hardware called tensor cores. DirectML will run on AMDs compute cores which MS want to use to upscale low resolution textures, so texture sizes remain small. If you listen to the 10GB too small crowd, having low resolution textures which are upscaled in a DLSS like process requires 16GB of vRAM.
AMd needs games to support all its custom amd fidelityfx feature just to get decent erformance on their hardware. Instead of RT Ambient Occlusion, you have Combined Adaptive Compute Ambient Occlusion (CACAO).
First of all, we moved the entire thing over to compute, allowing you the freedom to run it on either a compute or graphics queue. We've also done some major surgery on the data-transformations the effect undertakes. Finally, we also included an upsampler option to allow you to get high quality ambient occlusion within a budget that suits your game.
Enjoy the upsampling, this is a performance hack because using RT to do this costs to much performance on AMD hardware and is not true RT Ambient Occlusion. https://news.developer.nvidia.com/rtx-coffee-break-ray-traced-ambient-occlusion-417-minutes/
Drawbacks
- SSAO is a less-than-ideal process: it darkens the corners and edges in a scene, and leaves a dark halo around object borders.
- SSAO also can’t handle occlusion from offscreen geometry (or in-screen geometry, but occluded).
- Actually tracing rays around the geometry in the scene will be more physically correct than SSAO and gives you higher visual quality.
- Direct comparison between 2spp [2 sample per-pixel] Denoised and Ground Truth are strikingly close. SSAO is clearly less convincing.
- 1spp works pretty well for far-field occlusion, but for near field contact, we need to get to at least 2spp.
RT does the Ambient Occlusion effect with far better graphics quality with 2spp. it also can do offscreen geometry. It looks more real and natural.
AMD Stochastic Screen Space Reflections (SSSR) which is a performance hack for RT Reflections because their hardware is slower. The whole purpose is to reduce the number of rays needed and approximate RT reflections. https://www.ea.com/frostbite/news/stochastic-screen-space-reflections
In order to reduce the number of rays needed, we ray-trace at half-resolution, and reuse the rays shot from adjacent pixels in Monte Carlo integration. We can resolve to full resolution using several rays per pixel, but pay a small fraction of the ray-tracing.
This is why all AMD RT games have good performance on AMD hardware. They approx. many of the RT features and use upscaling to get the resolution required. This means image quality is reduced compared to the nvidia RT equivalent. This is why RT performance in Control is poor and performacne in dirt 5 is good. Control has no AMD performance hacks and just normal DXR features.
It's worth noting that this application was filed a year-and-a-half ago; AMD might have developed a new ray tracing system in the interim. But right now it seems like the company doesn't want to go the exact same route as Nvidia, which included dedicated ray tracing cores in Turing-based GPUs, and would rather use a mix of dedicated and non-dedicated hardware to give devs more flexibility. June 28, 2019
This is why the performance of RT is slower on AMD cards and there is no DLSS at the moment. AMD is rushing to develop super resolution with MS but nvidia won and the market wants full RT games and not a hybrid game like godfall etc with very light use of RT. Yet to listen to AMD fans the super resolution feature will be out next week and just as good a native.
MS in all of this wants the full RT feature set. https://www.gsmarena.com/microsoft_...et_the_full_rdna_2_feature_set-news-46450.php
Last edited: