https://www.jianshu.com/p/610507f53824/

L1/L2 Cache速度差别

L1 cache: 3 cycles
L2 cache: ~14 cycles
L3 cache: ~50 cycles

Main Memory: ~250 cycles

Pentium M:
To Where Cycles
Register  <= 1
L1d  ~3
L2  ~14
Main Memory ~240

https://www.jianshu.com/p/e338b550850f
从CPU到大约需要的 CPU 周期大约需要的时间

主存 约60-80纳秒

QPI 总线传输 (between sockets, not drawn)
约20ns

L3 cache 40-45 cycles,约15ns
L2 cache 约10 cycles,约3ns
L1 cache 约3-4 cycles,约1ns

寄存器 1 cycle