Short for Level 2 cache, L2 cache, secondary cache, or external cache, L2 is specialized, high-performance computer memory located on the die of the CPU. Unlike Layer 1 cache, L2 cache was located on the motherboard on earlier computers, although with newer processors it is found on the processor chip. It is located closer to the CPU, and therefore has lower latency, than the L3 cache.
The L2 cache is on the same processor chip and uses the same die as the CPU, however, it is still not part of the core of the CPU.
L2 cache was first introduced with the Intel Pentium and Pentium Pro computers and included with every subsequent processor, except some versions of the Celeron processor. This cache is not as fast as the L1 cache, but is only slightly slower since it is still located on the same processor chip, and is still faster than the computers memory. The L2 cache is the second thing the computer looks at when performing instructions.