High-Bandwidth Memory (HBM) is a special type of memory designed for AI chips. Traditional computer memory sits separately on a circuit board, but HBM stacks multiple memory chips vertically — like floors in a skyscraper — and places them directly next to the processor. This architecture dramatically increases data transfer speed. AI models need to process enormous datasets quickly; HBM can move data 10-20 times faster than conventional memory, making it essential for training and running large AI systems.
An AI GPU is only as fast as the memory feeding it data. High-Bandwidth Memory (HBM) — vertically stacked DRAM chips — is the critical component. Just three companies supply the entire world.
HBM Market Share (Q2 2025)
🇰🇷SK Hynix (South Korea)62%
🇺🇸Micron (United States)21%
🇰🇷Samsung (South Korea)17%
SK Hynix developed the first HBM in 2013 when demand was negligible. When the AI boom arrived, it dominated instantly. DRAM inventories collapsed to 2–4 weeks by October 2025. Shortages may persist until late 2027.
Memory Technology
🇺🇸 US & Allies🇨🇳 China
Key Relationships
SK Hynix → Nvidia
Primary HBM supplier for every generation of Nvidia AI GPUs.
SK Hynix → TSMC
HBM4 co-packaged with logic. Tight vertical integration.
Samsung: Memory + Foundry
Unique horizontal integration. Quality issues have limited HBM leverage.