> At over 2,500 t/s, Cerebras has set a world record for LLM inference speed on the 400B parameter Llama 4 Maverick model, the largest and most powerful in the Llama 4 family. This is incorrect. The unreleased Llama 4 Behemoth is the largest and most powerful in the Llama 4 family. As for the speed record, it seems important to keep it in context. That comparison is only for performance on 1 query, but it is well kno…
Performance per watt is better than h100 and b200, performance per watt per $ is worse than B200, and it does fp8 just fine https://arxiv.org/pdf/2503.11698
Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
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Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#92Earlier quoted context omitted.
The CSE-3 is divided into 900,000 PEs, which each have only 48kB of RAM: https://hc2024.hotchips.org/assets/program/conference/day2/7... Similarly, the SMs in Blackwell have up to 228kB of RAM: https://docs.nvidia.com/cuda/archive/12.8.0/pdf/Blackwell_Tu... If you need anything else, you need to load it from elsewhere. In the CSE-3, that would be from other PEs. In Blackwell, that would be from on package DRAM. Idle…
I don't really see how NVIDIA shipping so many chips matters. If more people want Cerebras chips they will presumably be manufactured. I agree that Cerebras manufacture I don't really see how that matters though. I don't see how core counts matter, but I assume that Cerebras is some kind of giant VLIW-y thing where you can give different instructions to different subprocessors. I imagine that the model weights would…
Mistral is a small fish in the grander scheme of things. I would assume that using Cerebras is a way to try to differentiate themselves in a market where they are largely ignored, which is the reason Mistral is small enough to be able to have their needs handled by Cerebras. If they grow to OpenAI levels, there is no chance of Cerebras being able to handle the demand for them.
Finally, I had researched this out of curiosity last year. I am posting remarks based on that.
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#93Earlier quoted context omitted.
Last year, I took the time to read through public documents and estimated that their annual production was limited to ~300 wafers per year from TSMC. That is not Nvidia level scale, but it is scale. There are many companies that sell tokens from an API and many more that need hardware to compute tokens. Cerebras posted a comparison of hardware options for these companies, so evaluating it as such is meaningful. It is…
> There are many companies that sell tokens from an API I was just at Dell Tech World and they proudly displayed a slide during the CTO keynote that said: "Cost per token decreased 4 orders of magnitude" Personally speaking, not a business I'd want to get into.
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#94Earlier quoted context omitted.
The processes used for logic chips, and the processes used for NVM are typically different. The only case I know of the industry combining them onto a single chip would be Texas Instruments’ MSP430 microcontrollers with FeRAM, but the quantities of FeRAM are incredibly small there and the process technology is ancient. It seems unlikely to me that the rest of the industry will combine the processes such that you can…
> The only case I know of the industry combining them onto a single chip would be Texas Instruments’ MSP430 microcontrollers with FeRAM Every microcontroller with on-chip NVM would count. Down to 45 nm, this is mostly Flash, with the exception of the MSP430's FeRAM. Below that... we have TI pushing Flash, ST pushing PCM, NXP pushing MRAM, and Infineon pushing (TSMC's) RRAM. All on processes in the 22 nm (planar) rang…
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#95Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#96Earlier quoted context omitted.
Only an insignificant minority of companies are running their own AI LLM models. Everyone else is perfectly fine using whatever Azure, GCP etc provide. Enterprise companies don't need to be the fastest or have the best user experience. They need to be secure, trusted and reliable. And you get that by using cloud offerings by default and only going third party when there is a serious need.
If you think that cloud offerings are secure and trustworthy by default you truly must be living under a rock.
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#97Earlier quoted context omitted.
I don't really see how NVIDIA shipping so many chips matters. If more people want Cerebras chips they will presumably be manufactured. I agree that Cerebras manufacture I don't really see how that matters though. I don't see how core counts matter, but I assume that Cerebras is some kind of giant VLIW-y thing where you can give different instructions to different subprocessors. I imagine that the model weights would…
You replied really quickly when I had thought I could sneak in a revision, which dropped the estimates for production numbers. In any case, the Cerebras CSE-3 is extremely inefficient for what it does. Inference is memory bandwidth bound, such that peak performance for a single query should be close to the memory bandwidth divided by the weights. Despite having. 2600x the memory bandwidth, they can only perform 2.5 t…
On WSE-3s however, there's enough memory that the model can actually be stored on-chip provided that you have a sufficient number of them. 20 are enough for some of the largest open models.
This, depending on how it's set up, allows more efficient use of what logic is available, for actually doing computations instead of just loading and unloading the weights. This can potentially make a system like this much more efficient than a GPU.
It doesn't matter whether Mistral are small fish or not. I don't agree that they are small fish, but whether or not they are they are experts. They are very capable people. They haven't chosen Cerebras to be different, they've chosen it because they believe it's the best way to do inference.
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#98Earlier quoted context omitted.
You replied really quickly when I had thought I could sneak in a revision, which dropped the estimates for production numbers. In any case, the Cerebras CSE-3 is extremely inefficient for what it does. Inference is memory bandwidth bound, such that peak performance for a single query should be close to the memory bandwidth divided by the weights. Despite having. 2600x the memory bandwidth, they can only perform 2.5 t…
Inference is memory bandwidth bound on a GPU, which has very little on-chip memory. On WSE-3s however, there's enough memory that the model can actually be stored on-chip provided that you have a sufficient number of them. 20 are enough for some of the largest open models. This, depending on how it's set up, allows more efficient use of what logic is available, for actually doing computations instead of just loading…
If you do the math you will find that Cerebras loses in all of them. They need 460 kW from 20x CSE-3 nodes to do inference for Llama 4 Maverick. A single DGX-200 node only needs 14.4kW. If you buy 32 nodes so that power consumption is the same and naively give each a full copy of the model, you would get 32,000 T/sec aggregate from a batch size of 1 while the 20 CSE-3 node cluster only gets 2,500 T/sec aggregate from a batch size of 1. This is having spent only $16 million for the 32 DGX B200 nodes versus the $40 million for the 20 CSE-3 nodes. Each DGX B200 node has 1.4TB of memory, while the CSE-3 cluster has only 880GB of memory. The CSE-3 cluster will run out of memory as you scale the batch size and context length. Now, if you buy another 15 CSE-3 nodes, you could match the memory of a single DGX B200, but then you could just store partial models on each DGX-200 like how Cerebras stored partial models on each CSE-3, and suddenly, you have more memory to scale to higher batch sizes on the Nvidia hardware. At some point, you will likely become compute bound and cannot keep scaling up the batch size, but that is hard to predict without actually testing for it. The prediction for what the CSE-3 could do based on advertised memory bandwidth was off by a factor of >1000 when given real data. It seems reasonable to think that what it can do as far as compute will similarly be limited to well below the theoretical capability.
Note that my numbers for power consumption were from Cerebras:
https://www.cerebras.ai/blog/cerebras-cs-3-vs-nvidia-b200-20...
Interestingly, the peak number for the DGX B200 is based on the power supplies for the DGX B200 and is actually 0.1 kW higher than Nvidia’s specification that puts it at 14.3kW:
https://docs.nvidia.com/dgx/dgxb200-user-guide/introduction-...
PSU peak output is always in excess of the maximum power usage capability of the hardware, but I did not know how Cerebras determined their 23kW figure, so I went with the Cerebras figure for Nvidia, even though I know it is unrealistically high. This likely gave Cerebras the benefit of a handicap on Nvidia’s hardware in the comparison, such that reality is even more in favor of Nvidia.
Calling Cerebras’ hardware the best way of doing inference is ridiculous. We are talking about doing mostly linear algebra. There is no best way of doing it. Pointing at Mistral to say that Cerebras has the best way is an absurd appeal to authority. None of the major players are using them, since they are incapable of handling their needs. The instant responses are nice and are a way for mistral to differentiate itself, but their models are not as good as those from others and few people use them, which is why Cerebras has the capacity to handle their needs.
From a historical standpoint, Cerebras is very similar to Thinking Machines Corporation, which went out of business after 11 years when there was a market downturn because they could not secure business. Cerebras is hemorrhaging money and is only in business because they found some investors willing to cover their losses. Once they run out of people willing to give them money (likely during the next AI winter), they will become insolvent, no matter how good their technology is. When the next AI winter hits, Mistral will likely become insolvent too, since they similarly are hemorrhaging money and are only in business because they found some investors willing to cover their losses.
By the way, you are lecturing someone who actually has worked on code for doing inference:
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#99Earlier quoted context omitted.
Inference is memory bandwidth bound on a GPU, which has very little on-chip memory. On WSE-3s however, there's enough memory that the model can actually be stored on-chip provided that you have a sufficient number of them. 20 are enough for some of the largest open models. This, depending on how it's set up, allows more efficient use of what logic is available, for actually doing computations instead of just loading…
Your “more efficient” remarks are nonsensical to me. Your “loading and unloading weights” remark would be slightly less nonsensical if you called it to Von Neumann bottleneck, but unfortunately for you, their hardware is so bottlenecked internally that they they are getting less than 0.1% of the performance that their supposedly high memory bandwidth can give them. Nvidia on the other hand routinely gets 80% or highe…
I will have to think through your comment, but won't be able to do so properly this month.
Re: Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)
#100Earlier quoted context omitted.
Inference is memory bandwidth bound on a GPU, which has very little on-chip memory. On WSE-3s however, there's enough memory that the model can actually be stored on-chip provided that you have a sufficient number of them. 20 are enough for some of the largest open models. This, depending on how it's set up, allows more efficient use of what logic is available, for actually doing computations instead of just loading…
Your “more efficient” remarks are nonsensical to me. Your “loading and unloading weights” remark would be slightly less nonsensical if you called it to Von Neumann bottleneck, but unfortunately for you, their hardware is so bottlenecked internally that they they are getting less than 0.1% of the performance that their supposedly high memory bandwidth can give them. Nvidia on the other hand routinely gets 80% or highe…