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Nvidia paid $20 billion because GPUs can't do fast inference

Andrew Feldman, CEO of Cerebras, talks to Matt Turk about why wafer-scale chips beat GPUs at inference, the three shortages that constrain GPU makers, and a decade of nobody buying.

Andrew FeldmanCerebrasNvidiaOpenAITSMCSemiconductorsInferenceAI InfrastructureData Centers
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Nvidia paid $20 billion because GPUs can't do fast inference

Recorded 26 July 2026 · 72 min

Fast inference is a memory-movement problem, not a compute problem. Generating each word means moving a model's weights from memory to compute, about 100 HD movies' worth for a 70 billion parameter model, and GPUs do it over slow HBM. Cerebras keeps the weights in SRAM on a dinner-plate-sized wafer and claims the move is about 2,500 times faster.

Andrew Feldman, co-founder and CEO of Cerebras, talks with Matt Turk on the Mad Podcast just after a record semiconductor IPO and an OpenAI deal worth more than $20 billion. The tension is between a decade in which nobody wanted his chip and a present in which demand outruns supply everywhere. He argues the shortages hitting rivals do not touch him and that CUDA no longer protects Nvidia. The harder questions, about lab-financed demand and his own move into renting data center capacity, get confident but thinner answers.

  1. Speed becomes the product — ▶ 2:06

    AI was a parlor trick until around the middle of 2025, when models got smart enough to use. Once tokens are productive, fast tokens are worth more, and the metric becomes tokens per second per user, first token to last. Agentic flows multiply the problem because waiting is amplified across multi-cycle turns. Feldman's analogy is Netflix: when the internet got fast it did not get better at mailing DVDs, it became a movie studio. Speed lets users stay longer, return more often and "work on harder problems". The market for dial-up, he says, is zero.

  2. Groq price as admission — ▶ 8:10

    Nvidia's most durable moat, Feldman says, was the perception that the GPU could do everything. Buying Groq for $20 billion, and doing it fast, told the market that GPU architecture could not do fast inference and that the segment was large and growing. Cerebras sales were more than 10 times Groq's, so Nvidia paid $20 billion for the number two player. He frames every chip as an ASIC in some sense: the TPU cannot do graphics, and each design is better at some things and much worse at others.

  3. OpenAI reads the curve — ▶ 9:15

    The OpenAI contract is north of $20 billion, which Feldman calls probably one of the largest deals in Silicon Valley history. His read on OpenAI: it looks at an exponential adoption curve and is not afraid of what it says. Others had to strike really bad deals for capacity, while OpenAI locked in memory and compute early, with Cerebras and others. The usual order is inverted: often people build and hope demand comes, but here the whole industry is chasing usage that already exists. He also calls a multi-silicon market healthy, citing x86's two-player decades, lost to ARM when phones arrived.

  4. China as industrial adversary — ▶ 12:10

    Feldman calls China an industrial adversary rather than a chip rival. It is behind in chips but has invested heavily in power and the grid, a real US weakness, and it produces very good open source models that trail GPT, Anthropic and Gemini. He sees possible Chinese leadership in power, which data centers need. Cerebras does not sell there, for regulatory reasons and some geopolitical ones. On local AI, he says phones and laptops are battery constrained, so the big work goes to the data center, which is where Cerebras focuses.

  5. Not a bubble, he argues — ▶ 17:24

    Asked whether lab-financed demand is fragile, Feldman says Cerebras has dozens of other customers trying to place very big orders. Bubbles, in his account, are supply getting ahead of demand: 1990s fiber was laid years early and took 6 to 8 years to fill. Now everyone is trying to catch up, only a small part of the world uses AI near its potential, and he says the industry is "overwhelmed" with demand for compute and memory. On market swings, public markets vote in the short term and weigh in the long term. He ignores the daily moves.

  6. Three shortages, none his — ▶ 19:07

    Every GPU and ASIC except Cerebras uses DRAM, specifically HBM, made by three companies: SK Hynix, Samsung and Micron. It is sold out, and only new factories add supply. TSMC's CoWoS process, a silicon motherboard used by Nvidia and AMD, is sold out too. Capacity at 3 nanometers is congested, and most of the GPU world is there. Cerebras uses none of the three: its architecture avoids HBM and CoWoS, and its chips are on 5 nanometers. The chip is 58 times the size of a GPU with 2,500 to 3,000 times the memory bandwidth.

  7. Agents drive CPU demand — ▶ 23:21

    Agentic AI initiates action: visiting a website, pulling data from storage, ordering a burrito. CPUs execute all of it. Feldman's metaphor is the accelerator as brain and CPUs as body, so each increment of agentic work generates more CPU calls. That is pushing CPU demand "through the roof", and CPUs hit the same memory shortages as accelerators. It is a second-order effect of agents that most chip talk about GPUs and ASICs misses, and it connects the shortage story to how AI is actually being used.

  8. Ten years of bad timing — ▶ 25:51

    "The way you have perfect timing is to have horrible timing for 10 years." Cerebras started in 2016, four years after ImageNet, when everything was vague and nascent. The design rule was never to embed the latest model in circuitry, which Feldman calls a historical structural mistake. Its architecture predates transformers yet is fastest at them, and it was fastest at diffusion before diffusion had an architecture. The bet is on the underlying calculation, sparse linear algebra. From SeaMicro, sold to AMD, he carried two questions: can this be made faster, and is there enough of it?

  9. Be 50 times better — ▶ 30:26

    Feldman told VCs up front that you never beat Nvidia by being a little better: they buy everything for less, apply pricing pressure and bundle. The target was 10 to 50 times better. HBM stores a lot but is slow, while SRAM is unbelievably fast but stores little. In graphics, work dominates data movement. In inference it reverses, because all the weights move for one calculation. The fix is a part the size of a dinner plate stuffed with SRAM. The prior biggest chip was 840 sq mm, while this is 46,000, cut from one 300 mm wafer.

  10. The unknown hard part — ▶ 33:56

    No vendors existed for a part that looks like nothing else ever made, so power delivery, cooling and packaging had to be invented. For 18 months the company spent $8 million a month and could not build the chip. What everyone feared was easy. What nobody knew to fear, affixing a wafer to a motherboard and powering and cooling it, was the hard part. A failure analysis on every failure got them through, and they announced success in August 2019. Redundancy is designed in: about a million identical tiles, failed ones shut down and spares used. Water cooling keeps temperatures down.

  11. Decode is the bottleneck — ▶ 41:37

    Inference has two steps. Prefill processes the prompt and can be parallelized. Decode generates the answer one word at a time, and it cannot be parallelized. Each word requires moving the model's weights from memory to compute. For a 70 billion parameter model that is about 100 HD movies' worth of data, moved again for every word, for perhaps 1,000 words. That exact step is where HBM is slow. Because Cerebras holds the weights in SRAM, it moves them about 2,500 times faster than a GPU. Faster inference also speeds RL, which runs inference inside training.

  12. Reasoning widens the gap — ▶ 48:30

    Reasoning works like drafting in eighth grade: break the problem into parts, solve, review, improve, answer. It takes more compute at inference, and on slow hardware that is crippling. Every leading model, domestic or Chinese, has moved to it. Feldman calls that a huge advantage for Cerebras, because GPU slowness stacks up while its speed advantage widens. Verification and guardrails cost more passes: re-ask the question differently, score the answer. His preferred pattern is a big model writing and a small model checking, like a journalism data checker verifying each claim independently.

  13. Hardware shifts to cloud — ▶ 54:28

    Cerebras sells hardware for customers' data centers or rents capacity from its own. The mix was 50/50 last year, about 75/25 hardware last quarter, maybe 50/50 this year, and he expects 30/70 hardware to cloud as the OpenAI deal unfolds. That deal is 750 megawatts: 250 in 2026, 250 in 2027 and more in 2028, on multi-year leases, delivered as a full cloud through an API. Data center availability is a limiting constraint for everybody. He is building in the Nordics for clean, cheap power and cooling, and keeping data centers on the same continent as customers because of fiber latency.

  14. CUDA is not a moat — ▶ 1:01:05

    Feldman rejects CUDA as a moat. Two years ago every state-of-the-art model was trained in a CUDA flow. Now Gemini trains on TPUs, Claude on Trainium, and only OpenAI still uses CUDA. He says Nvidia lost 70% share of training for leading models in a year or two. In inference there is no moat at all: it takes "eight keystrokes" to move traffic from a GPU API to Cerebras. He concedes CUDA was enormously important to the industry's creation and the moat has shrunk rather than vanished. His own moat is architectural: rivals cannot simply spend their way to fast.

  15. Nobody cared in 2020 — ▶ 1:06:53

    Cerebras delivered a chip no one in computing history had built in 2020, and "Nobody cared." The first generation sold 20 or 30 units, the second 300 to 500, and the third tens of thousands. AI was a hobby then, and nobody cares whether a hobby is fast. Speed matters once AI is in production and used daily. He says first chips rarely win: Google's TPU was good only on the fourth try and is now on its eighth, and AWS's chip was good on the second or third. TSMC agreed to Cerebras's 2017 proposal in the meeting, and the first chip took 2 years.

The open question. Feldman answered the circular-financing question with history: bubbles happen when supply outruns demand, and today's problem is the reverse. That may be true of usage and still miss the question of who pays for it. He did not quantify the lab-funded share of demand. The other customers were only "dozens" placing big orders, with no names and no share. With the OpenAI deal pushing the mix toward 70% cloud, Cerebras also takes on the data center and power scarcity he calls a limit for everybody. Watch how much of the 750 megawatts is live in 2026, and who else signs a multi-year lease.

Watch the full video at https://www.youtube.com/watch?v=UEOSUSz--Ig.

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