From Sand to Superintelligence · Drill cards · Chapter 24
Drills
Memory's Pyramid
10 atomic recall cards. Export to Anki and let spaced repetition do its slow work.
In Anki: File → Import, choose this TSV, set field separator to Tab, deck = Sand to Silicon · Ch 24, note type = Basic.
| Front | Back |
|---|---|
| What is the approximate latency of a register access? | ~1 cycle. |
| What is the approximate latency of an L1 cache access? | ~3–4 cycles. |
| What is the approximate latency of an L3 cache access? | ~40 cycles. |
| What is the approximate latency of a DRAM access? | ~300 cycles — the 300× cliff the pyramid exists to hide. |
| What size range does L3 cache span, and what qualifies the two ends? | 8–64 MB: consumer CPUs at the low end (8–32 MB), server-class parts at the high end. |
| What is a cache line, and how big is it on x86? | The unit of data movement between cache levels — 64 bytes on x86 and most ARM; 128 bytes on Apple Silicon. |
| What is temporal locality? | The tendency of programs to reuse recently accessed memory locations soon after accessing them. |
| What is spatial locality? | The tendency of programs to access memory addresses near recently accessed ones. |
| What does the TLB cache, and what is a typical L1 TLB size? | Virtual-to-physical address translations. The L1 TLB often holds around sixty-four entries. |
| What is the memory wall? | The growing gap between CPU speed and DRAM speed — documented by Hennessy and Patterson as roughly doubling every few years through the 1990s. |