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Raytracing on Intel's Arc B580

Raytracing on Intel's Arc B580

67 comments

·March 16, 2025

achierius

It feels like just yesterday that Chips and Cheese started publishing (*checked and they started up in 2020 -- so not that long ago after all!), and now they've really become a mainstay in my silicon newsletter stack, up there with Semianalysis/Semiengineering/etc.

> Intel uses a software-managed scoreboard to handle dependencies for long latency instructions.

Interesting! I've seen this in compute accelerators before, but both AMD and Nvidia manage their long-latency dependency tracking in hardware so it's interesting to see a major GPU vendor taking this approach. Looking more into it, it looks like the interface their `send`/`sendc` instruction exposes is basically the same interface that the PE would use to talk to the NOC: rather than having some high-level e.g. load instruction that hardware then translates to "send a read-request to the dcache, and when it comes back increment this scoreboard slot", the ISA lets/makes the compiler state that all directly. Good for fine control of the hardware, bad if the compiler isn't able to make inferences that the hardware would (e.g. based on runtime data), but then good again if you really want to minimize area and so wouldn't have that fancy logic in the pipeline anyways.

atq2119

> both AMD and Nvidia manage their long-latency dependency tracking in hardware

This is incorrect for AMD, which has "s_waitcnt" instructions in its ISA, which is publicly documented. I believe it is also incorrect for Nvidia, but don't have the receipts to prove it.

im_down_w_otp

I love these breakdown writeups so much.

I'm also hoping that Intel puts out an Arc A770 class upgrade in their B-series line-up.

My workstation and my kids' playroom gaming computer both have A770's, and they've been really amazing for the price I paid, $269 and $190. My triple screen racing sim has an RX 7900 GRE ($499), and of the three the GRE has surprisingly been the least consistently stable (e.g. driver timeouts, crashes).

Granted, I came into the new Intel GPU game after they'd gone through 2 solid years of driver quality hell, but I've been really pleased with Intel's uncharacteristic focus and pace of improvement in both the hardware and especially the software. I really hope they keep it up.

throwaway48476

They won't make a B770 or C770 because they lose money on every card they sell. The prices are low because otherwise they would sell 0 and they already paid for the silicon. The intel graphics division is run by fools who won't give their cards a USP in the SR-IOV feature home labers have been asking for for years. Doing what AMD and Nvidia do but worse is not a profitable strategy. There's a 50% the whole division gets fired in the next year though.

freddi333

SR-IOV doesn't sell consumer cards, are you expecting Intel to produce an expensive XEON equivalent of Arc? I'd expect them to attempt capturing some LLM market share by loading up the cards with RAM rather than expending effort on niche features.

throwaway48476

SR-IOV would sell more cards than Intel would be able to sell if they charged market rate for their GPUs. Same goes for not selling a local LLM high VRAM variant. Intel is just allergic to competing by offering a USP.

AMD Ryzen CPUs have ECC enabled but not officially supported. Intel still locks away the feature.

gruez

>The intel graphics division is run by fools who won't give their cards a USP in the SR-IOV feature home labers have been asking for for years.

Intel are "fools" for not adding a feature that maybe a few thousand people care about?

throwaway48476

A few thousand people is a lot more than the number of gamers who'd buy an Intel GPU at market price. If they don't raise their ASP into the black they're going to ax the whole division.

For reference the B580 die is nearly the size of the 4070 but sells for a third the price.

999900000999

I have a couple of these too, and I strongly believe Intel is effectively subsidizing these to try to get a foothold in the market.

You get me equivalent of a $500 Nvidia card for around $300 or less. And it makes sense because Intel knows if they can get a foothold in this market they're that much more valuable to shareholders.

Great for gaming, no real downsides imo.

DeepSeaTortoise

They should drop a $600 card with 128gb of vram. This is just barely possible without losses on every sale.

And then just watch heads explode.

ryao

At current market pricing on dramexchange, 128GB of 16Gbit GDDR6 chips would cost $499.58. That only leaves $100.42 for the PCB, GPU die, miscellaneous parts, manufacturing, packaging, shipping, the store’s margin, etcetera. I suspect that they could not do that without taking a loss.

I wonder if they could mix clamshell mode and quadrank to connect 64 memory chips to a GPU. If they connected 128GB of VRAM to a GPU, I would expect then to sell it for $2000, not $600.

ryao

They are definitely selling them at close to no profit, but they are not anywhere near subsidizing them unless they botched their supply chain so badly that they are overpaying the BOM costs.

999900000999

R&D isn't free.

Even selling at cost is a subsidy.

I'm proud to support them. Intel is also selling their lunar lake chips fairly cheaply too. Let's all hope they make it through this rough patch. I can't imagine a world where we only have one x86 manufacturer.

rayiner

This is so cool! I think this is a video of CyberPunk 2077 with path tracing on versus off: https://www.youtube.com/watch?v=89-RgetbUi0. It sees like a real, next-generation advance in graphics quality that we haven't seem in awhile.

vinkelhake

Just a heads up - it looks like the "Path Tracing Off" shots have ray tracing disabled as well. In the shots starting at 1:22 (the car and then the plaza), it looks like they just have the base screenspace reflections enabled. Path tracing makes a difference (sometimes big, sometimes small) for diffuse lighting in the game. The kind of reflection seen in those scenes can be had by enabling "normal" ray tracing in the game, which is playable on more systems.

fracus

Ray tracing is more intensive than "path tracing". From my understanding, they are the same with the only difference being that "path tracing" does less calculations by only considering a light source's most probable or impactful paths or grouping the rays or something. Neither scene is using "ray tracing".

sergiotapia

Was raytracing a psyop by Nvidia to lock out amd? Games today don't look that much nicer than 10 years ago and demand crazy hardware. Is raytracing a solution looking for a problem?

https://x.com/NikTekOfficial/status/1837628834528522586

im_down_w_otp

I've kind of wondered about this a bit too. The respective visual quality side of it that is. Especially in a context where you're actually playing a game. You're not just sitting there staring at side by side still frames looking for minor differences.

What I have assumed given then trend, but could be completely wrong about, is that the raytracing version of the world might be easier on the software & game dev side to get great visual results without the overhead of meticulous engineering, use, and composition of different lighting systems, shader effects, etc.

kmeisthax

For the vast majority of scenes in games, the best balance of performance and quality is precomputed visibility, lighting and reflections in static levels with hand-made model LoDs. The old Quake/Half-Life bsp/vis/rad combo. This is unwieldy for large streaming levels (e.g. open world games) and breaks down completely for highly dynamic scenes. You wouldn't want to build Minecraft in Source Engine[0].

However, that's not what's driving raytracing.

The vast majority of game development is "content pipeline" - i.e. churning out lots of stuff - and engine and graphics tech is built around removing roadblocks to that content pipeline, rather than presenting the graphics card with an efficient set of draw commands. e.g. LoDs demand artists spend extra time building the same model multiple times; precomputed lighting demands the level designer wait longer between iterations. That goes against the content pipeline.

Raytracing is Nvidia promising game and engine developers that they can just forget about lighting and delegate that entirely to the GPU at run time, at the cost of running like garbage on anything that isn't Nvidia. It's entirely impractical[1] to fully raytrace a game at runtime, but that doesn't matter if people are paying $$$ for roided out space heater graphics cards just for slightly nicer lighting.

[0] That one scene in The Stanley Parable notwithstanding

[1] Unless you happen to have a game that takes place entirely in a hall of mirrors

corysama

Yep. I worked on the engine of a PS3/360 AAA game long ago. We spent a long of time building a pipeline for precomputed lighting. But, in the end the game was 95% fully dynamically lit.

For the artists, being able to wiggle lights around all over in real time was an immeasurable productivity boost over even just 10s of seconds between baked lighting iterations. They had a selection of options at their fingertips and used dynamic lighting almost all the time.

But, that came with a lot of restrictions and limitations that make the game look dated by today’s standards.

bee_rider

I get the pitch that it is easier for the artists to design scenes with ray-tracing cards. But I don’t really see why we users need to buy them. Couldn’t the games be created on those fancy cards, and then bake the lighting right before going to retail?

(I mean, for games that are mostly static. I can definitely see why some games might want to be raytraced because they want some dynamic stuff, but that isn’t every game).

gmueckl

When path tracing works, it is much, much, MUCH simpler and vastly saner algorithm than those stacks of 40+ complicated rasterization hacks in current rasterization based renderers that barely manage to capture crude approxinations of the first indirect light bounces. Rasterization as a rendering model for realistic lighting has outlived its usefulness. It overstayed because optimizing ray-triangle intersection tests for path tracing in hardware is a hard problem that took some 15 o 20 years of research to even get to the first generation RTX hardware.

gruez

>When path tracing works, it is much, much, MUCH simpler and vastly saner algorithm than those stacks of 40+ complicated rasterization hacks in current rasterization based renderers that barely manage to capture crude approxinations of the first indirect light bounces.

It's ironic that you harp about "hacks" that are used in rasterization, when raytracing is so computationally intensive that you need layers upon layers of performance hacks to get decent performance. The raytraced results needs to be denoised because not enough rays are used. The output of that needs to be supersampled (because you need to render at low resolution to get acceptable performance), and then on top of all of that you need to hallu^W extrapolate frames to hit high frame rates.

juunpp

This doesn't hold at all. Path tracing doesn't "just work", it is computational infeasible. It needs acceleration structures, ray traversal scheduling, denoisers, upscalers, and a million other hacks to work any close to real-time.

juunpp

Except that it isn't like that at all. All you get from the driver in terms of ray tracing is the acceleration structure and ray traversal. Then you have denoisers and upscalers provided as third-party software. But games still ship with thousands of materials, and it is up to the developer to manage lights, shaders, etc, and use the hardware and driver primitives intelligently to get the best bang for the buck. Plus, given that primary rays are a waste of time/compute, you're still stuck with G-buffer passes and rasterization anyway. So now you have two problems instead of one.

keyringlight

I think there's two ways of looking at it. Firstly that raster has more or less plateaued, there haven't been any great advances in a long time and it's not like AMD or any other company have offered an alternative path or vision for where they see 3d graphics going. The last thing a company like nvidia wants is to be a generic good which is easy to compete with or simple to compare against. Nvidia was also making use of their strength/long term investment in ML to drive DLSS

Secondly, nvidia are a company that want to sell stuff for a high asking price, and once a certain tech gets good enough that becomes more difficult. If the 20 series was just a incremental improvement from the 10, and so on then I expect sales would have plateaued especially if game requirements don't move much.

sergiotapia

I don't believe we have reached a raster ceiling. More and more it seems like groups are cahoots to push rtx and ray tracing. We are left to speculate why devs are doing this. nvidiabux? easier time to add marketing keywords? who knows... i'm not a game dev.

https://www.youtube.com/watch?v=NxjhtkzuH9M

gruez

There's no need for implications of deals between nvidia and game developers in smoke filled rooms. It's pretty straightforward: raytracing means less work for developers, because they don't have to manually place lights to make things look "right". Plus, they can harp about how it looks "realistic". It's not any different than the explosion of electron apps (and similar technologies making apps using html/js), which might be fast to develop, but are bloated and feel non-native. But it's not like there's an electron corp, giving out "electronbux" to push app developers to use electron.

phatfish

Raster quality is limited by how much effort engine developers are willing to put into finding computationally cheap approximations of how light/materials behave. But it feels like the easy wins are already taken?

gambiting

>>We are left to speculate why devs are doing this.

Well, I am a gamedev, and currently lead of a rendering team. The answer is very simple - because ray tracing can produce much better outcomes than rasterization with lower load on the teams that produce content. There's not much else to it, no grand conspiracy - if the hardware was fast enough 20 years ago to do this everyone would be doing it this way already because it just gives you better outcomes. No nvidiabux necessary.

berkut

Not if you want better fidelity: the VFX industry for film moved from rasterisation to raytracing / pathtracing (on CPU initially, and a lot of final frame rendering is still done on CPU due to memory requirements even today, although lookdev is often done on GPU if the shaders / light transport algorithms can be matched between GPU/CPU codepaths) due to the higher fidelity possible starting back in around 2012/2013.

It required discarding a lot of "tricks" that had been learnt with rasterisation to speed things up over the years, and made things slower in some cases, but meant everything could use raytracing to compute visibility / occlusion, rather than having shadow maps, irradiance caches, pointcloud SSS caches, which simplified workflows greatly and allowed high-fidelity light transport simulations of things like volume scattering in difficult mediums like water/glass and hair (i.e. TRRT lobes), where rasterisation is very difficult to get the medium transitions and LT correct.

ThatPlayer

I don't think it's just about looks. The advantage of ray tracing is the real time lighting done rather than the static baked maps. One of the features I feel that was lost with modern game lighting is dynamic environments. But as long as the game isn't only ray tracing, these types of interactions will stay disabled for the game. Teardown and The Finals are examples of a dynamic environment game with raytraced lighting.

Another example is when was the last time you've seen a game with a mirror that wasn't broken?

gruez

Hitman, GTA, both of which use a non-raytraced implementation. More to the point, lack of mirrors doesn't impact the gameplay. It's something that's trotted out as a nice gimmick, 99% of the time it's not there, and you don't really notice that it's missing.

keyringlight

Hitman is an example that contradicts your point about gameplay, guards will see you in mirrors and act appropriately. They'll be doing that for gameplay with a non-graphical method, but you need to show it to the player graphically for them to appreciate the senses available

ThatPlayer

GTA V's implementation did not work in their cars. Rear view and side view mirrors in cars are noticeably low quality and missing other cars while driving, which is pretty big for gameplay purposes.

Working mirrors are limited to less complex scenes in GTA. Hitman too I believe.

Clemolomo

[dead]

washadjeffmad

If you think of either crypto or gaming and not accelerated compute for advanced modeling and simulation when you hear Nvidia, you won't have sufficient perspective to answer this question.

What does RTX do, what does it replace, and what does it enable, for whom? Repeat for Physx, etc. Give yourself a bonus point if you've ever heard of Nvidia Omniverse before right now.

davikr

lol, go play Cyberpunk 2077 with pathtracing and compare it to raster before you call it a gimmick.

sergiotapia

i own an rtx 4090 and yes cyberpunk looks amazing with raytracing - but worth the $2000k and nvidia monopoly over the tech? a big resounding no (for me).

Clemolomo

It's a transition happening.

Research and progress is necessary, Ray tracing is a clear advancement.

AMD could just easily skip it if they want to reduce costs, we could just not by the gpus. Non of it is happening.

It does look better and it would be a lot easier if we would only do ray tracing

shmerl

If suggested usage means upscaling, it's a dubious trade off. That's why I'm not using it in Cyberpunk 2077, at least with RDNA 3 on Linux, since I don't want to use upscaling.

Not sure how much RDNA 4 and on will improve it.

christkv

Arc will be successful because it will be in all mobile chips. The individual gpu market is smaller by a big factor and they are targeting the biggest part of that market with low cost.

api

Intel Arc could be Intel's comeback if they play it right. AMD's got the hardware to disrupt nVidia but their software sucks and they have a bad reputation for that. Apple's high-end M chips are good but also expensive like nVidia (and sold only with a high-end Mac) and don't quite have the RAM bandwidth.

blagie

Intel is close. Good history with software.

If they started shipping GPUs with more RAM, I think they'd be in a strong position. The traditional disruption is to eat the low-end and move up.

Silly as it may sound, but a Battlemage where one can just plug in DIMMs, with some high total limit for RAM, would be the ultimate for developers who just want to test / debug LLMs locally.

userbinator

Silly as it may sound, but a Battlemage where one can just plug in DIMMs, with some high total limit for RAM, would be the ultimate for developers who just want to test / debug LLMs locally.

Reminds me of this old satire video: https://www.youtube.com/watch?v=s13iFPSyKdQ

throwaway48476

Intel is run by fools. I don't see them coming back. They just don't have the willingness to compete and offer products with USPs. Intel today is just MBAs and the cheapest outsourced labor the MBAs can find.