What Memory Hierarchy Design Involves
Registers offer the fastest access but hold only a handful of values. Local caches or SRAM buffers sit close to compute units, trading some capacity for much lower latency and higher bandwidth than off-chip memory. Larger shared caches serve multiple cores or accelerators. Off-chip DRAM or HBM provides the bulk capacity needed for large datasets, at a significant latency and power cost compared to on-chip storage.
Why It Matters
For many workloads – especially AI/ML and signal processing – moving data costs far more energy than computing on it. A well-designed memory hierarchy that maximizes on-chip data reuse can be the difference between a chip that hits its power budget and one that doesn't.