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Crytek Shows 4K 30 FPS Ray Tracing On Non-RTX AMD and NVIDIA GPUs (techspot.com)
dryriver writes: Crytek has published a video showing an ordinary AMD Vega 56 GPU -- which has no raytracing specific circuitry and only costs around $450 -- real-time ray tracing a complex 3D city environment at 4K 30 FPS. Crytek says that the technology demo runs fine on most normal NVIDIA and AMD gaming GPUs. As if this wasn't impressive already, the software real-time ray tracing technology is still in development and not even final. The framerates achieved may thus go up further, raising the question of precisely what the benefits of owning a super-expensive NVIDIA RTX 20xx series GPU are. Nvidia has claimed over and over again that without its amazing new RTX cores and AI denoiser, GPUs will choke on real-time ray tracing tasks in games. Crytek appears to have proven already that with some intelligently written code, bog ordinary GPU cores can handle real-time ray tracing just fine -- no RTX cores, AI denoiser or anything else NVIDIA touts as necessary.
That video doesn't prove anything. It could be completely pre-rendered. If it isn't, why not show someone actually moving around the scene with a mouse?
Turing (Nvidia) has exactly ZERO ray tracing units. All 'ray' algorithm maths calculations are done on the standard shader cores- same as with this demo on the AMD Vega 56. So what gives?
An ex-Nvidia engineer post on Beyond3d gave the game away. This engineer was partially responsible for the so-called 'ray tracing' enhancement on Turing. Put simply, this is what Turing does:
a = b + c * d
say the above is a ray maths calc (obviously it is not). The '+' and '*' are the maths operations done on the usual shaders. What every tech site misses is that there is another issue- the process that gets the VARIABLES to the shader ALU blocks.
What Nvidia did with Turing was to add tiny ASIC circuits that allow the VARIABLES that represent triangles and rays to be more efficiently moved to the STANDARD shader units from the other units (like geometry). No RT 'cores' (there are no such thing in Turing) but a tiny logic hack that allowes the GPU to be reconfigured to move certain kinds of data much faster to the shader cores.
However the significance of this is that if one arranges for ray/triangle data to be held in a more efficient form on a 'normal' GPU, the same ray 'acceleration' can be achieved.
Not that even on Turing does REAL-TIME ray tracing happen. Real ray tracing needs far too many 'bouncy' rays per screen pixel to ever be possible on any ordinary GPU- and the problem with real ray tracing is MEMORY COHERENCE, not the maths of the ray/triangle collision.
Turing 'ray tracing' is actually simple ray algorithms applied to real-time reflection maps (NOT true reflection) and shadows. Metro Exodus tried a very very basic form of ray averaging for lighting, which was no better than simply using more traditional light sources.
And the tensor cores on Turing? Well unlike the non-existent ray tracing cores, the Tensor cores are real and use vast numbers of transistors. Why are the Tensor cores real- and the main reason Turing exists? Because Nvidia spent hundreds of millions of dollars developing new crypto currency mining algorithms to run exclusively on Tensor. However, crypto currency collapsed between Turing's design and release. Nvidia's future GAMING GPUs will not have tensor cores.
Turing was 100% designed to displace AMD in the PC crypto currency mining space. Nvidia lost an absolute fortune with Turing cos of the collapse (and Nvidia actually reported this fact at its investor conferences in 2018).
PS all practical 'ray' algorithms can be far better done (faster, less energy) using traditional raster algorithms. Light probe lighting methods with voxel data sets do the real time lighting more than good enough. Real time reflection maps do not need 'ray tracing' to deploy in reflection enhancement. Same applies to shadows- where good enough is better than extreme GPU power/processing requirements.
Indeed, with shadows, the minor improvements to near shadows are not the issue- the issue is shadows being disabled beyond a certain z-distance- something ray methods actually make worse. Better shadows = MORE shadows and shadows across more of the scene.
I was super excited to play 4K the day I bought my shinny new 4K TV. But since then I have chosen 1080P over 4K on both my GTX 1080 and my PS4 Pro as the frame rate is waaaaaaaaayyyyyyyy more important than resolution.