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Why Top Founders Are Racing Into AI Infrastructure

Ben Horowitz, Martin Casado, Raghu Raghuram, and Erik Torenberg discuss the launch of a16z's new Machine Age Fund and the infrastructure buildout behind AI, from chips, memory, and networking to power, cooling, and data centers. Why a dedicated fund now? The group argues that the bottleneck in AI is increasingly shifting from the models themselves to everything beneath them. Hyperscaler CapEx is surging, critical components are booked years in advance, and each new generation of reasoning and agents requires dramatically more compute. They unpack why this cycle looks different from previous infrastructure booms and how AI is turning problems once constrained by engineering into problems that can increasingly be attacked with capital and compute. They also explore where the next generation of infrastructure companies could emerge, why founders are returning to hard technical problems across hardware and systems, and what it will take to rebuild the computing stack for the Machine Age. Timestamps: 00:00 - Intro 00:50 - Introducing the Machine Age Fund 02:00 - Why Founder Interest in Hardware Just 4x'd 04:00 - How Do We Know Demand Isn't a Hype Cycle? 07:00 - Sold Out to 2028: The Unprecedented Supply Crunch 10:00 - What's Actually Bottlenecked Right Now 14:00 - Tokens, Scaling & Why There's No Natural Regulator 19:00 - Agents as a New Kind of Employee: The GrokBot Moment 25:00 - What "AI-Designed" Infrastructure Actually Looks Like 28:00 - Rack Power, Liquid Cooling & the Data Center Redesign 34:00 - 44 Gigawatts by 2028: Why Building Faster Is So Hard 38:00 - Why "Machine Age" Is the Right Name 40:00 - Won't Incumbents Like Nvidia Take Everything? 48:00 - The Founder Profile: Why Hardware Needs Experience Resources: Read more about the Machine Age Fund : https://www.a16z.news/p/the-machine-age-fund Follow Ben Horowitz on X: https://x.com/bhorowitz Follow Raghu Raghuram on X: https://x.com/RaghuRaghuram Follow Martin Casado on X: https://x.com/martin_casado Stay Updated: If you enjoyed this episode, be sure to like, subscribe, and share with your friends! Find a16z on X: https://twitter.com/a16z Find a16z on LinkedIn: https://www.linkedin.com/company/a16z Listen to the a16z Show on Spotify: https://open.spotify.com/show/5bC65RDvs3oxnLyqqvkUYX Listen to the a16z Show on Apple Podcasts: https://podcasts.apple.com/us/podcast/a16z-podcast/id842818711 Follow our host: https://x.com/eriktorenberg Please note that the content here is for informational purposes only; should NOT be taken as legal, business, tax, or investment advice or be used to evaluate any investment or security; and is not directed at any investors or potential investors in any a16z fund. a16z and its affiliates may maintain investments in the companies discussed. For more details please see http://a16z.com/disclosures.

Ben HorowitzguestRaghu RaghuramguestErik Torenberghost
Aug 28, 202653mWatch on YouTube ↗

At a glance

WHAT IT’S REALLY ABOUT

AI’s explosive demand is forcing a full-stack infrastructure rebuild

  1. a16z announces the “Machine Age Fund,” premised on the view that AI is the biggest technology shift since electricity and requires an entirely new infrastructure stack.
  2. The speakers argue demand for AI compute is structurally accelerating—especially with agents—while supply is constrained across chips, memory, power, cooling, construction, and permitting, with capacity effectively booked out to 2028 in key components.
  3. They describe a data-center redesign driven by extreme rack power density (moving toward 100–250kW), shifts from AC to DC power and air to liquid cooling, and growing constraints in materials and skilled labor.
  4. They claim AI’s scaling dynamics have fewer natural “governors” than traditional software engineering, making physical resource expansion and efficiency improvements the central limiter and opportunity.
  5. They contend incumbents will capture large markets, but the scale and fragmentation of needs plus lab desperation and abundant capital create room for new, well-capitalized, systems-oriented hardware/software startups.

IDEAS WORTH REMEMBERING

5 ideas

AI has turned scaling into a resource-supply problem, not just an engineering problem.

They argue AI is unlike prior software waves because demand for “intelligence” is effectively unbounded, and progress often comes from spending more on compute rather than being limited by team coordination (the “Mythical Man-Month” constraint). This shifts the limiting factor to physical capacity—chips, memory, power, cooling, and facilities.

Multiple market indicators suggest a real, persistent supply crunch—not a hype cycle.

Signals include hyperscalers rapidly increasing CapEx (discussed as approaching ~$1T collectively), GPU prices reversing their historical downward trend, multi-day GPU auctions, and critical components being pre-sold years out. They contrast this with the dot-com era, where much infrastructure was speculative (e.g., dark fiber) rather than fully utilized.

The bottlenecks are “everything, simultaneously,” from mines to megawatts.

They describe constraints spanning the entire stack: GPUs, memory (with a cited three-year backlog from a leading vendor), power availability, cooling, reinforced concrete, high-voltage/DC electricians, transformers, turbines, and permitting. The claim is that many of these lead times are intrinsically hard to compress.

Agents amplify compute demand because they multiply both tokens per task and number of tasks.

As AI moves from chat to reasoning to agents and multi-agent systems, token usage per task can jump by orders of magnitude, while the user base expands from developers to knowledge workers and beyond. Agents that operate computers like employees (e.g., “GrokBot”) are presented as a new demand step-function.

AI-native infrastructure requires re-architecting from silicon to the building shell.

They predict redesign across chips, memory hierarchies, interconnect, and data-center architecture, including a shift from ~5–10kW racks toward ~100–250kW racks, air to liquid cooling, and AC to DC power distribution. Facilities must change too (weight, noise, water usage, and community impact).

WORDS WORTH SAVING

5 quotes

We have a whole new technology that's the most important technology ever, and you need a whole new infrastructure.

Ben Horowitz

Normally, when we talk about the infrastructure world, we're talking about the servers and the storage and the network. Here, it goes all the way down to the mines, copper mines.

Raghu Raghuram

The supply, if you lo- if you look at the supply across the board, it's basically all booked out to 2028. I mean, it's so bad, we've actually seen multi-day auctions for a few thousand GPUs.

Unknown

It used to be when you built something, it was an engineering problem... And here it feels like it really is a resource limitation.

Unknown

Nine women can't have a baby in a month. That, like, that's it. Like, that never works. Okay, now that works.

Ben Horowitz

Machine Age Fund thesisDemand signals vs. hype-cycle riskGPU/memory shortages and supply booked to 2028Token economics and scaling via inferenceAgents and “AI as employee” (GrokBot)Data-center redesign: rack density, DC power, liquid coolingPermitting, labor, and grid/power constraints (gigawatt scale)

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