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Reiner Pope – Chip design from the bottom up

Explore episode May 22, 2026
Technology
Why almost all chip area is wasted on moving data

Reiner Pope – Chip design from the bottom up · May 22, 2026 Technology

In a classic CPU or CUDA core, 7/8 of the circuit area is consumed by MUX circuits just to read and write the register file — not by actual computation. The multiply-accumulate unit you care about is a tiny fraction of the silicon. This is the fundamental problem that Tensor Cores and systolic arrays were invented to solve.

Where this was said

Muxes and the cost of data movement

At 20:20 · chapter starts 16:31

Traces a CUDA core / CPU data path: register file → MUX → ALU → write back. Shows that 7/8 of circuit area is consumed by MUX data movement, not computation.

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