What is HBM4 and how does it differ from HBM3E?

HBM4 doubles bandwidth to 2 TB/s per stack using a 2048-bit interface at 8 Gb/s pins, versus HBM3E's 1024-bit at up to 9.8 Gb/s. Wider, not faster.

When will HBM4 hit production and who makes it?

Samples now, mass prod 2026 from SK Hynix, Samsung, Micron. NVIDIA Rubin first customer.

No—it shifts it right by two years. Physics limits pin speeds; width scales linearly, but AI needs exponential gains.

🤖 AI & Machine Learning

HBM4 doubles bandwidth without breaking pin-speed records. It just made the pipe twice as wide, dodging physics for now.

theAIcatchup Apr 08, 2026 3 min read

HBM4 doubles bandwidth to 2TB/s via 2048-bit width, not higher pin speeds. 𝕏
Signal integrity walls cap pins at ~10 Gb/s; widening is the pragmatic fix. 𝕏
Echoes CPU multi-core pivot—buys time, but AI compute will hit limits again soon. 𝕏

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#AI hardware #GPU memory #HBM4 #High Bandwidth Memory #JEDEC specs #memory bandwidth

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Originally reported by Dev.to