● dense/○ explainer
aileena·machina
investing · 2026 · jun

Five PCBs sit inside a current-generation AI rack.

Why mainland China is winning the board fight in 2026 — and which one decides 2027.

— tldr —

five boards. mainland China leads on three. the fight that matters is SLP at 10 µm — new clean-room plants only, no retrofits.

An AI rack is a sandwich of five PCBs stacked together. Each one has its own supplier fight. The map is moving fast enough that two consecutive Rubin generations could ship with completely different vendor lists.

the five boards

HDI · computeswitchmid plane44-layer · orthogonalorth. backplaneSLP · 10 µm
1
2
3
4
5

the rack, opened up · five boards, top to bottom

① computeVictory Giant ~90%
· GB200 / GB300
② switch32-layer
M9 consensus
③ mid planereplaces 5,000+
copper cables
④ backplanecopper-sintered
78–104 layers
⑤ SLP · 202710 µm = new
clean-room plants
↘ GB200 row
2027 decider

why the mid plane exists

Blackwell racks connect compute boards to switch boards through 5,000+ copper cables. Assembling the bundle is the named reason GB200 deliveries slipped.

in plain wordstoo many wires. they replaced them with one rigid skeleton.

The 576-rack architecture drops the cables for an orthogonal backplane — every drawer plugs into the same rigid PCB skeleton. The mid plane is the drawer-level version of the same shift.

↓ the fight today ↓

three barriers

SLP at 10 µm. Needs new clean-room plants. Avary has Apple SLP DNA; Victory Giant is committing capex.

barrier 1new factory, not
a retrofit. capex bet.

M9 + Q-cloth. Retires mechanical drilling. Han’s Laser opens to >60% domestic share.

barrier 2old drill retires.
laser takes over.

Copper sintering for mid plane + backplane is industry-first, execution-speed-led.

barrier 3first to ship
at yield wins.

the google sidebar

Forecast revised 2.5–3M → 4M TPU chips at ~$9k each. Uses 22–24 layer multi-high, not HDI. ISU / Wus / ChaoYing incumbent. Victory Giant queuing for ~6 month certification.

← dispatch