Beware of “structural bloodletting”: a sober reflection on the DRAM industry behind the HBM4 frenzy

HBM4 ramp masks a deeper supply shock

It has been reported that Samsung Electronics (三星电子) has secured NVIDIA certification for its HBM4 and will begin mass production in the third week of February, immediately after Lunar New Year. The move — enabled by an aggressive mix of 1c nm DRAM process and a 4nm logic base die — shores up AI compute supply. But it also accelerates what the industry is calling a “structural bloodletting” of global DRAM wafer capacity as fabs reallocate lines from commodity DDR products to high-margin HBM. Who wins the AI race — and who pays for it — are two very different questions.

Tech and economics: a cruel arithmetic

The technical trade-offs are stark. HBM4 uses 16‑Hi stacking and hybrid bonding; yields are reportedly only around 55% versus 90%+ for DDR5, and producing equivalent capacity consumes 2.5–3× the wafer area of DDR5, per SemiAnalysis’s Dylan Patel. TrendForce data shows the three major DRAM makers’ HBM capacity has surged to roughly 355,000 wafers/month, lifting HBM’s share of global DRAM wafer starts from 8% two years ago to about 23% today. The result is a brutal allocation decision: HBM4 margins sit in the 65–70% range while general‑purpose DDR5 margins linger near 30%. With capex finite, suppliers chase the higher margin product.

Downstream fallout and the Chinese opening

The upstream reallocation is rippling through the supply chain. Price indices show DDR4 has seen far steeper relative increases (reportedly up ~1,800% year‑over‑year in some comparisons) than DDR5 (~500%), producing “tail‑end” shortages that slam low‑end PCs, industrial controllers and IoT devices. TechInsights has warned of a 2026 supply‑chain reshuffle where mid‑tier assemblers are squeezed between rising upstream costs and weak pricing power downstream. That gap has created an opening for China’s domestic DRAM players. ChangXin Memory Technologies (长鑫存储) — while still only some 8–10% of global share by one estimate — has concentrated mature‑node capacity that can backfill the vacated DDR4/DDR5 segments; it reportedly accounts for roughly 40% of China’s general‑purpose DRAM supply today. But this is largely an “eating the leftovers” opportunity, not parity in high‑value HBM, GDDR or cutting‑edge logic.

Strategic chokepoints and geopolitical backdrop

The scramble for HBM4 also exposes other bottlenecks. It has been reported that CoWoS‑L advanced packaging capacity is already booked through Q3 by Nvidia and AMD, meaning memory that is built cannot always be integrated into modules. At the same time, advances in logic fabs (SMC’s reported strong N2 yields) and the U.S.-led export control regime, plus Beijing’s push for semiconductor self‑sufficiency, amplify the strategic stakes: supply decisions are now technical, commercial and geopolitical. The short‑term AI bonanza may look like a golden era for memory majors, but the industry’s structural shift risks long‑term fragmentation — and a painful price to pay for everyone downstream.