AI hardware · Layer

High-bandwidth memory (HBM)

Stacks of DRAM placed right next to the GPU die to feed it data fast enough. AI workloads are often memory-bandwidth bound, so HBM capacity and speed frequently set the practical ceiling on performance.

Key facts

HBM is built by vertically stacking DRAM dies and connecting them with through-silicon vias, then placing the stack beside the processor on a shared interposer.
Only three companies make HBM at scale: SK Hynix, Samsung, and Micron.
Each HBM generation (HBM3, HBM3E, HBM4) raises bandwidth and capacity, and supply is typically sold out generations in advance.
HBM is one of the tightest links in the whole AI hardware chain: a shortage here throttles finished accelerator output directly.

Where it bottlenecks

HBM yield and capacity are a primary supply limit; qualifying new HBM on an accelerator is slow and a single supplier can constrain the market.

Who dominates it

SK HynixSamsungMicron

Companies in this layer

Kioxia

Japan

NAND flash memory manufacturer for AI data storage and SSDs

Micron

United States

The third major HBM supplier and a large memory maker.

Samsung

South Korea

Major HBM and DRAM supplier and an alternative leading-edge foundry.

SK Hynix

South Korea

Leading supplier of high-bandwidth memory for AI accelerators.

All companies across the chain

Explore other layers

GPUs and AI accelerators Chip foundries and fabrication Advanced packaging Lithography and fab equipment Networking and interconnect AI servers and systems Data centers Cooling and thermal management Supply constraints and bottlenecks

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