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The Nvidia Turing GPU Architecture Deep Dive: Prelude to GeForce RTX
- jaytaylor 8y agoOn mobile all I see is the comments section. Friendlier link: https://www.anandtech.com/print/13282/nvidia-turing-architecture-deep-dive https://www.anandtech.com/print/13282/nvidia-turing-architec...
- mrep 8y agoHappened for me on desktop too probably because the link is a comments link. Mods, can you change the link?
- KaoruAoiShiho 8y agoThis is the link you want: https://www.anandtech.com/show/13282/nvidia-turing-architecture-deep-dive https://www.anandtech.com/show/13282/nvidia-turing-architect... Both the article and comments.
- ramshanker 8y agoOne Desktop as well. I thought it was my ad blocker going on steroids !
- jaytaylor 8y agoSo the new top-end Nvidia cards will have dedicated ray tracing cores. However, real-time ray tracing is still so computationally expensive that games can only implement a hybrid form of it whereby ray tracing is applied for a certain effect or single object, and plain old rasterization is used for everything else. I applaud NV for stepping up and delivering something in a new direction. Just think- how long has it been since something truly new has been introduced in the gfx world? Reading through the full article, it was no small feat to dream up and build these cards. A very complex project from both product and engineering perspectives. Hardware-wise, the 2080 specs are quite insane, and these babies are thirrrsty, drawing ~250 watts. That said, the move definitely seems risky, as it increases complexity significantly for game devs to code for this hybrid approach. What if the market doesn't warm up to this, or perhaps ATI or someone else comes up with something more novel? I also wonder if it's just a few years premature. Not feeling compelled to give up the good old 970GTX yet. Wake me up when full ray tracing is ready :) --- P.S. I couldn't help but snicker when looking at the table near the end showing which games will support what new imaging modes. Of course, PUBG doesn't support ray tracing. Hardly a surprise, considering they can't patch without hours of downtime, and also frequently deliver patches containing "fixes" which break more than they fix. (FWIW I've stopped PUBG and moved on to Elite:Dangerous, aka space truckers, thanks to it being recommended in an HN thread. Fun game, if you enjoy the solitude of loneliness of endless space! ;)
- jarfil 8y ago10 GigaRays/sec = 80 rays per pixel at 1080p60fps. That should be enough to do full scene real-time raytracing with rays per pixel to spare (usually 10 rays per path are more than enough).
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- zokier 8y agoLooking at the demo video Nvidia released yesterday[1], it is pretty obvious that the performance is still bit limited. The shadows and reflections are distinctly low-resolution and I don't think its solid 60fps either. Sure it's still pretty nice for first-gen product, so not complaining too much. But there is still fair bit of road to go on. [1] Atomic Heart: Official GeForce RTX Real-Time Ray Tracing Demo https://www.youtube.com/watch?v=1IIiQZw_p_E https://www.youtube.com/watch?v=1IIiQZw_p_E
- MBCook 8y agoI was under the impression from the initial coverage that they were actually getting something like 1 to 2 rays per pixel per frame. Perhaps even less. From there they were using some sort of smoothing and/or temporal anti-aliasing to gather the data from multiple frames to get decent quality out of it. Or are you proposing how many raise they would NEED to be able to do real time full raytracing? By the time we have that ability I imagine everyone will just want the 4K version anyway and we will be behind again. Either way what nVidia has shown looks great. It’s too bad I’ll have to wait years to be able to use it as a console gamer.
- Covzire 8y agoWhy does ray tracing require more than 1 ray per pixel anyway?
- exDM69 8y agoFor the secondary rays for reflection, refraction and shadows. At one ray per pixel, you can only do the primary ray and find which triangle it hits. The exact same thing can be done with rasterization much faster and with equal results.
- rl3 8y agoThe Turing architecture is also used in Quadro RTX cards, and those have a ridiculous amount of VRAM. Is there any professional/computational use for these RT cores beyond raytracing? One case that comes to mind is perhaps raytracing acoustics, and although interesting it's technically still raytracing. As far as gaming is concerned, personally I'd love if the RT cores could contribute—however inefficiently—to rendering workload in non-RTX games. It's annoying that 50% of the die is allocated to hardware that requires feature-specific implementations.
- kbwt 8y ago> It's annoying that 50% of the die is allocated to hardware that requires feature-specific implementations. That's the future. While we may be able to cram more transistors onto "7nm" chips, only a tiny fraction of the chip area can be powered on because leakage currents are no longer decreasing with transistor size [1]. Hence Apple's Neural Engine and Nvidia's RTX. You have to waste the extra transistor count on something specialized. [1] https://semiengineering.com/is-dark-silicon-wasted-silicon/ https://semiengineering.com/is-dark-silicon-wasted-silicon/
- rl3 8y agoThe RT and Tensor cores are primarily intended to power raytracing and DLSS, respectively. Both of those features will be used in conjunction with traditional shading/compute units, so the entire die is utilized at once, at least at a high level. It would be really interesting to know the power consumption of a Turing card maxing out just its shading units, versus full utilization with RTX/DLSS.
- jsheard 8y agoThe whitepaper brings up physics simulation and occlusion/visibility testing as possible non-raytracing applications of the RT hardware, plus acoustic simulation as you said. Page 30: https://www.nvidia.com/content/dam/en-zz/Solutions/design-visualization/technologies/turing-architecture/NVIDIA-Turing-Architecture-Whitepaper.pdf https://www.nvidia.com/content/dam/en-zz/Solutions/design-vi...
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- npunt 8y agoThe thing that strikes me with the RTX announcement is a general point about how important identifying useful intermediate steps are to bringing about new paradigms. Unless a technological breakthrough is just around the corner, or you have the resources to push it forward (Space Race / Manhattan Project), it’s better to spend your energy identifying useful intermediate steps that you can offer to the market to fund & bridge yourself to the new paradigm. By having funding all along the way, you can gain a significant advantage to those pursuing the new elegance directly. [1] A few examples: STREAMING. People used to go to video stores to rent movies. As the internet emerged we dreamed of a new, more elegant paradigm: streaming. No more driving to a store, no more physical copy or late fees or damages, etc. But it was the clever discovery of an intermediate step - to use the internet to rent DVDs via mail - that created the brand and customer base that established the market leader (Netflix). Once internet infrastructure caught up, the switch was seamless. Meanwhile, there were many people who pursued streaming directly, but failed because they didn’t take the intermediate step (Broadcast.com). ELECTRIC CARS. Traditional cars have super complex drivetrains. As battery tech improved, we dreamed of a new, more elegant paradigm of electric vehicles that improved efficiency and eschewed most moving parts, transmissions, exhaust systems, etc. But there existed a valuable, infrastructure-free intermediate step to get there: hybrids. Ironically they were even more complex, but they employed many new techs that helped move electric cars forward. Toyota has hugely benefitted from being the discoverer of this intermediate step. Obviously we now have Tesla leading the vanguard, but in the context of global development, nobody can predict if an Elon will show up in your generation. AUGMENTED REALITY. Our current physical reality is awash in information - street signs, road paint, branding, menus, maps, clocks, games, warnings, nutrition labels, interfaces, etc. These are often completely irrelevant to us at a given time, and certainly not personalized to our needs. We dream of the day we can render overlays on our eyes to deliver the personalized versions of these (as well as entirely new things), which would over time mean our physical reality would get simpler, cleaner, and less wasteful. To deliver this elegant solution requires a lot of breakthroughs in display technology that are years if not decades away. Bundling SLAM tech into smartphones (looking at you Apple) and pursuing incremental use cases is an intermediate step that can grow the market until the point where the displays are ready, at which point those who best pursue this are likely to be the market leader. Ray tracing is now on the same course. It's been known for decades that it is a far more elegant paradigm to reason about and generate images (vis-a-vis rasterization), but its compute requirements are so high that there's been this chasm people haven't been able to cross to get to ray tracing. Nvidia has now provided a bridge between these two worlds, by allowing raytracing of parts of the rendering pipeline alongside rasterization. Subsequent generations will slowly swallow the remaining parts that rasterization performs today. Basically the RTX is the graphics card equivalent of a Prius, growing into a full electric. The addition of ray-tracing cores in the RTX line was a pleasant surprise to me, not only because it speeds the development of ray-tracing hardware, but because it showed intermediate steps existed that I didn’t know about before. It showed me we weren’t stuck waiting indefinitely for a promise of an elegant future that always seems a decade away. Pretty exciting. [1] What I mean by paradigm is not just incrementalism or an evolution of one product into another (like iPod -> iPhone), but of a wholly different way to solve a problem that is more elegant / higher abstraction than previous ways, but that require breakthroughs in enabling technologies to get there. Rockets -> Space Elevators (material science; elegance is in ease of transport), Retail -> Online Shopping (internet; elegance is in personalization + stay-at-home), Coal -> Solar (energy storage; elegance is in eco footprint, low entry point & simpler tech), Driving -> Autonomous Driving (ML/sensors; elegance is in time savings / one less thing to learn & simplification+density of road infra). This is admittedly a fuzzy definition, and perhaps these examples are not perfect.
- CoolGuySteve 8y agoWhy are RT cores so different than normal shader cores? What instructions/memory fetch does a ray trace operation do that couldn't be implemented as an added instruction set on the shader cores to navigate the volume tree? From the article, the best I can see is the following, but can't that be solved with microcode or as an extra rendering pipeline stage? > In comparison, traversing the BVH in shaders would require thousands of instruction slots per ray cast, all for testing against bounding box intersections in the BVH I ask, because having more slightly larger general purpose cores seems better for traditional rendering and raytracing than dedicating all that die space to pure single-purpose RT cores.
- exDM69 8y agoIt is more like a texture unit than a shader core. Tree traversal is a pointer chasing problem, where the CPU/shader core executes a few instructions, then starts a memory load and then sits idle for tens or hundreds of clock cycles waiting for memory. Cache prefetching can help but is usually not a good fit for tree traversal where there is very little computation per node. It is all about memory latency hiding and not really about computation.
- kbwt 8y agoBut GPU cores are already king at latency hiding. They can run hundreds of threads doing pointer chasing, switching between them round-robin as the memory reads complete.
- exDM69 8y agoThe switching isn't free. Waking up a thread to do just a few computation cycles (a few ray-aabb intersections) and then going back to sleep while waiting for the next node to be fetched from the memory is super inefficient. If there was significant computation needed per node, this wouldn't be an issue.
- kbwt 8y ago> The switching isn't free. It absolutely is, on current GPUs. Think of it like a larger-scale version of SMT (Intel's hyperthreading). GPUs are able to do this because they execute instructions in-order and do not need to track thousands of instructions per thread.
- marvin 8y agoSeems to me like ray-traced rendering provides a feasible path to foveated rendering for VR, meaning much better performance for VR scenes at high resolutions. This would be a big deal for VR developers, since they don't have to do unlikely amounts of magic to implement this. If NVIDIA is able to drag everyone along, they will get the hardware for this without making any huge strategic moves on their own part.
- beerlord 8y agoWe are at the end of the console cycle, which means games hardware requirements will plateau until the next gens are out. So from now, at 1080p, a 1070 is enough to handle everything at 60fps until then. That probably translates to a 2060 this generation - which is the card I'm really interested in. Other than that Nvidia cards are severely restricted due to their lack of support for Adaptive Sync or HDMI 2.1 VRR.
- zokier 8y agoConsidering that 1070 is struggling already with some 2016 games[1], I find the claim that it would be able to handle everything until next console gen comes out (2020 earliest?) very dubious. [1] https://www.anandtech.com/bench/product/1941 https://www.anandtech.com/bench/product/1941
- beerlord 8y agoThere is only one game on that list - GTAV - that performs below 60fps. And for that game, its trivial to lower a few settings and hit 60.
- TwoQ 8y agoWill be interesting to see if this goes the way of PhysX or not.
- cjhanks 8y agoDon't forget that NVIDIA is not only a gaming company. They are involved in a lot of computational geometry fields, localization reconstruction, machine learning, etc. There are a lot of use cases for ray tracing that are not games. So far NVIDIA has done a great job at changing their GPU architecture in a way that is mutually beneficial to all of their diverse customer base.
- dan678 8y agoThe use case that seems obvious to me is computationally efficient ray-tracing in robotics/autonomy simulation. I wonder if ISAAC sim will take advantage of RTX. What do you think?
- cjhanks 8y agoI am not familiar with ISAAC, but it appears that ray tracing would be relevant in this case.