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Machine Learning Street Talk

The Thermodynamic AI Computing Chip - Thomas Ahle

62 min episode · 3 min read
·
Thomas Ahle

Episode

62 min

Read time

3 min

Topics

Productivity, Fundraising & VC, Leadership

AI-Generated Summary

Key Takeaways

  • Thermodynamic Computing Architecture: Normal Computing's CN-101 chip uses arrays of capacitors with programmable resistances to run stochastic differential equations natively. Rather than suppressing thermal noise, the chip harnesses it to compute matrix inverses probabilistically—operations that cost enormous resources on conventional hardware. This makes it particularly suited to Bayesian inference and probabilistic workloads where uncertainty quantification matters, though algorithm redesign is required to fully exploit the architecture.
  • AI Agent Chip Design at Scale: Ahle ran approximately 20 GPT agents continuously for six months to build a Verilog simulator from scratch, generating over 500,000 lines of code in 43 days. The motivation was cost: commercial EDA simulation tools run roughly $10,000 per CPU core, making large-scale agentic hardware workflows economically impossible with proprietary software. Open-source alternatives are nearly nonexistent in hardware, unlike software ecosystems.
  • Benchmark Deception in Hardware AI: Passing 80% of tests on hardware benchmarks does not mean a design is correct—if a program fails even one test, the implementation is likely wrong. Ahle spoke directly with creators of hardware benchmarks who confirmed this distinction. Practitioners should evaluate AI-generated chip designs on full test-suite pass rates, not partial scores, and treat percentage-based benchmark reporting as a misleading proxy for correctness.
  • Auto-Formalization for Chip Verification: Ahle applies a technique analogous to AlphaProof's IMO approach to hardware: language models generate formal specifications in lean-style languages, then attempt to prove or disprove properties of chip designs. A key training trick borrowed from AlphaProof—asking models to prove or disprove rather than just prove—removes the need for correct formalizations during training, enabling scalable synthetic data generation for reinforcement learning on verification tasks.
  • Understanding Debt in Agentic Codebases: Large agentic coding projects accumulate what Ahle calls understanding debt—code that passes tests but that no engineer has read or comprehends structurally. With 500,000-line AI-generated codebases, architectural decisions become opaque, blocking future evolution. The practical mitigation is to identify which subsystems require deep human understanding versus which are routine implementations, and deliberately preserve comprehension of the former even when delegating the latter to agents.

What It Covers

Thomas Ahle, researcher at Normal Computing, discusses thermodynamic computing chips that use electrical noise as computation rather than eliminating it, AI-assisted chip design using Verilog simulators built by swarms of agents, formal verification challenges in hardware, and the broader risks of AI-generated code eroding human understanding across engineering teams.

Key Questions Answered

  • Thermodynamic Computing Architecture: Normal Computing's CN-101 chip uses arrays of capacitors with programmable resistances to run stochastic differential equations natively. Rather than suppressing thermal noise, the chip harnesses it to compute matrix inverses probabilistically—operations that cost enormous resources on conventional hardware. This makes it particularly suited to Bayesian inference and probabilistic workloads where uncertainty quantification matters, though algorithm redesign is required to fully exploit the architecture.
  • AI Agent Chip Design at Scale: Ahle ran approximately 20 GPT agents continuously for six months to build a Verilog simulator from scratch, generating over 500,000 lines of code in 43 days. The motivation was cost: commercial EDA simulation tools run roughly $10,000 per CPU core, making large-scale agentic hardware workflows economically impossible with proprietary software. Open-source alternatives are nearly nonexistent in hardware, unlike software ecosystems.
  • Benchmark Deception in Hardware AI: Passing 80% of tests on hardware benchmarks does not mean a design is correct—if a program fails even one test, the implementation is likely wrong. Ahle spoke directly with creators of hardware benchmarks who confirmed this distinction. Practitioners should evaluate AI-generated chip designs on full test-suite pass rates, not partial scores, and treat percentage-based benchmark reporting as a misleading proxy for correctness.
  • Auto-Formalization for Chip Verification: Ahle applies a technique analogous to AlphaProof's IMO approach to hardware: language models generate formal specifications in lean-style languages, then attempt to prove or disprove properties of chip designs. A key training trick borrowed from AlphaProof—asking models to prove or disprove rather than just prove—removes the need for correct formalizations during training, enabling scalable synthetic data generation for reinforcement learning on verification tasks.
  • Understanding Debt in Agentic Codebases: Large agentic coding projects accumulate what Ahle calls understanding debt—code that passes tests but that no engineer has read or comprehends structurally. With 500,000-line AI-generated codebases, architectural decisions become opaque, blocking future evolution. The practical mitigation is to identify which subsystems require deep human understanding versus which are routine implementations, and deliberately preserve comprehension of the former even when delegating the latter to agents.
  • Continual Learning Trade-offs in Hardware: Analog neuromorphic substrates using capacitor-based memory require constant refreshing, making perpetual on-chip learning a practical necessity rather than a design choice. This mirrors biological synaptic plasticity. However, Anthropic and others treat real-time weight updates as a safety risk because live learning can drift models away from alignment checkpoints. Hybrid approaches using shared base models with per-customer LoRA adapters represent one partial solution currently being explored.

Notable Moment

Ahle describes a paradox in AI tool adoption: language models can genuinely accelerate knowledge acquisition for curious, diligent users, yet on average they erode understanding across teams. The mechanism is structural—engineers optimize for passing tests rather than comprehension, and AI enables starting so many parallel projects that deep understanding of any single one becomes impossible.

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Episode Transcript

Yeah. So why not try and build a chip that's just inherently random? Meet Thomas Arley. I caught up with him in Zurich and he's one of these rare galaxy brain people who's comfortable in probabilistic machine learning, formal verification, and chip design. However, there's a small problem. When the token god hands you something that looks like it works, how do you know it's actually right? So my background is in theoretical computer science. I used to do algorithms for high dimensional data locality sensitive hashing. Then I moved to normal computing to develop thermal computing, also to speed up Bayesian intelligence. Sometimes, I think about it as the lovable for chip design. So we take it all the way from your intent, through the design, through optimizing your design, to formalizing and verifying your design, all the way to tape out. Now, I didn't fully appreciate this before. These days a chip doesn't necessarily start in a factory. It can start as code. So engineers design the whole circuit in a language called Verilog, almost written like software, and only much later does any of it become physical silicon. But first, that code has to be simulated and formally verified. It has to be proven correct. Because once a chip is fabricated, if there are any bugs, you're in big trouble. So a few months ago, Thomas blogged about building a Verilog simulator using a swarm of AI agents collaborating with each other, and it generated over half a million lines of code in forty three days. Now the reason he needed to do this is that commercial software costs a ridiculous amount of money and isn't very friendly to using agents. $10,000 per seat or something. Yeah. Per for one CPU kernel. If an AI can generate a chip design or a proof or a working program, how do you know it's actually correct? The percentage of tests that it got right or like even like the fable, it was like, oh, yeah. It got, like, 80% tests correct. And it's like, yeah. But I talked with the people who made the benchmark and, like, yeah. But it did did it get any of them actually right, you know, like Now in chip design, noise is the enemy. Manufacturers spend a fortune getting rid of it. But in thermodynamic computing, the opposite is kind of true. The noise is the computation. It comes straight out of probabilistic machine learning, learning, which already runs on randomness and uncertainty. And thermodynamic computing tries to make the chip itself a stochastic differential equation. Let the chip's own noise settle into place, and then it can land on answers that would normally cost a fortune to compute. And then you infuse all of this noise, and it'll start to behave according to to to these, stochastic differential equations. It actually behaves sort of according to the inverse of that matrix. They've already released their first version of this technology. It's a …

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Books, tools, and gear mentioned in this episode

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Tools

  • Ahle ran approximately 20 GPT agents continuously for six months to build a Verilog simulator from scratch, generating over 500,000 lines of code in 43 days.
  • Ahle applies a technique analogous to AlphaProof's IMO approach to hardware: language models generate formal specifications in lean-style languages, then attempt to prove or disprove properties of chip designs. A key training trick borrowed from AlphaProof—asking models to prove or disprove rather than just prove—removes the need for correct formalizations during training.

Gear

  • by Normal Computing

    Normal Computing's CN-101 chip uses arrays of capacitors with programmable resistances to run stochastic differential equations natively. Rather than suppressing thermal noise, the chip harnesses it to compute matrix inverses probabilistically.

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