CompTIA A+ Certification All-in-One Exam Guide

improved performance tremendously. In fact, it helped so much that many
motherboard makers began adding a cache directly to the motherboards.
These caches were much larger, usually around 128 to 512 KB. When the
CPU looked for a line of code, it first went to the built-in cache; if the code
wasn’t there, the CPU went to the cache on the motherboard. The cache on
the CPU was called the L1 cache because it was the one the CPU first tried to
use. The cache on the motherboard was called the L2 cache, not because it
was on the motherboard, but because it was the second cache the CPU
checked.
Eventually, engineers took this cache concept even further and added the
L2 cache onto the CPU package. Many modern CPUs include three caches:
an L1, an L2, and an L3 cache (see Figure 3-28).