Textbook › Part I The Physics of Semiconductors
CHAPTER 13
Moving Data Costs More Than Computing
This chapter is short, but it may be the most important one for understanding AI hardware.
It runs against intuition, but on a modern chip, moving data costs far more energy than computing with it. The rough orders of magnitude look like this.
Energy per operation, as a rough order of magnitude
| Operation | Relative cost |
|---|---|
| 8-bit addition | 1 |
| 8-bit multiplication | a few times that |
| Read from on-chip SRAM | tens of times that |
| Read from off-chip DRAM | hundreds to thousands of times that |
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