On 6 July 2026, the research firm SemiAnalysis reported that NVIDIA's next big AI rack, Kyber, would slip from 2027 to 2028 (Tom's Hardware, CNBC). The reason it gave was not a chip. It was a circuit board. NVIDIA disputed it.

Either way, the argument is the story. Eight minutes. Here is the whole board.

📖 In plain words: the terms you need

Chip package. The small assembly that holds one or more chips and connects them to the outside world.

Package substrate. The small board inside the package that a chip is mounted on.

CoWoS. TSMC's advanced packaging, which places processor and memory side by side on a sliver of silicon.

HBM. High-bandwidth memory: stacked memory chips placed right next to an AI processor inside the package. Where to check it: our piece The Real AI Shortage Is Memory.

Co-packaged optics. Moving the part that turns electrical signals into light inside the switch chip's own package.

Midplane. One large, rigid circuit board in the middle of a rack that the processor and switch trays plug into, replacing cable bundles.

Glass core substrate. A plan to replace the organic core of a chip package substrate with a sheet of glass.

Interconnect levels. The different scales at which a computer is wired together, from inside a chip to across a data centre.

🎯 THE WHAT

The board is losing some work to the chip package at both ends: the shortest links and the longest ones. At the same time it is gaining work from the cables in the middle. What remains is harder to make, not easier.

Kyber is designed to link 144 of NVIDIA's processor packages in one cabinet, twice as many as the racks shipping today. Today's rack links its processors through more than 5,000 copper cables, about two miles in total. Kyber replaces them with a single rigid board, called a midplane.

SemiAnalysis said that board was proving "challenging from a manufacturability standpoint." Asian circuit board stocks fell on the report. NVIDIA told Yahoo Finance: "Our roadmap remains intact." A Mizuho analyst called the reports "headline-grabbing noise."

A serious analyst firm's best explanation for a possible delay in the most watched AI product was that a board was too hard to make.

Each level is made by a different industry. Picture it as a city: corridors inside a building, walkways between buildings, the campus grounds, the city streets, the roads between districts, and the highways between cities.

The rule of thumb: the shorter the trip, the faster and cheaper it is to move data. So engineers keep pulling the busiest traffic inward, onto the shortest route.

Movement 1, memory moves in. The busiest link in an AI system, processor to memory, used to cross a board. Now the memory sits beside the processor inside the package. That is why substrate makers are booming: Prismark reported that many leading substrate makers grew revenue 20% to 30% in 2025.

Movement 2, optics move in. The conversion from electricity to light used to happen in a plug-in module at the front of a switch, across a stretch of board. NVIDIA announced co-packaged optics switches in March 2025, claiming 3.5 times better power efficiency. Broadcom began shipping its third-generation version in October 2025. We covered the economics in When the Wires Cost More Than the Chips.

Movement 3, cables move down into the board. This is the counter-current most predictions missed. Kyber's midplane turns the roads between districts into city streets. Work that belonged to cables now belongs to the board.

Prismark reported that the global bare-board market grew 16.7% in 2025, to $85.8 billion, concentrated in high-layer boards for AI servers and networking.

The board is squeezed from both ends and filled in from the middle. It is losing the finest work and gaining the heaviest. What remains carries signals so fast that it needs more layers and rarer materials. That is why a midplane could plausibly delay a rack.

Glass core substrates replace the organic core of the chip package with a sheet of glass, which is flatter and more stable under heat. The most advanced effort is Absolics, a subsidiary of Korea's SKC, with a factory in Covington, Georgia. It was sampling to customers including AMD in 2026, aiming for mass production by late 2026 if customers certify it.

Samsung Electro-Mechanics has reportedly aimed at 2027. Intel has shown samples and describes its roadmap as targeting around 2030 (roadmap review).

Notice what glass core does not do. It replaces the core of the chip package, not the circuit board, and it does not escape glass. At the board level, the frontier material is quartz cloth, as Story 2 showed. Both escape routes lead further into specialty materials, not away from them.

Almost none of this describes an automotive board. A car's engine controller does not carry 200-gigabit signals, and nobody is replacing its wiring harness with co-packaged optics.

But because AI boards are getting thicker and more complex, they consume more laminate, more cloth and more factory time every year. The AI board is not a shrinking competitor for your supplier's capacity. It is a growing one. As Story 1 showed, TTM's chief executive described that pressure on automotive materials in August.

The question worth asking your suppliers is not when AI demand goes away. It is when new capacity for the grades you use catches up with it.

As of September 2026.

The investor read is analysis of industry structure, not investment advice. Nothing here is a recommendation to buy or sell any security. I hold no positions in the companies covered and take no payment from them. Do your own work.

🧭 THE WHERE

1. Tom's Hardware on the Kyber report, the clearest summary of the midplane problem [6 min]

2. Tom's Hardware: the glass substrate roadmap, examined [10 min]

3. The Room Where AI Runs, our own piece on what one AI rack demands [7 min]

PCB Story 1: Why Your PCB Quote Went Up
The price on your desk, and why buyers outside AI are waiting in a queue.

PCB Story 2: Your AI Cluster Runs on Cloth
Why a woven glass fabric decides what an AI computer can do.

PCB Story 3: Nobody Is Getting Rid of the Circuit Board (you are here)
Why the board keeps losing work to the chip package, and gets harder to make anyway.

PCB Story 4: The Map
Who makes the board, where, and how the map came to look this way.