L2 cache is the second tier of a multi-cache memory system and provides memory to a processor without delay. An L2 cache sits between an L1 and L3 cache and is generally either 256 KB or 512 KB in size. An L2 cache contains frequently used information and prevents the processor from having to search the L3 cache or RAM, which are both much larger in size. Although a processor will first search the L1 cache, it is often the L2 cache that contains the needed information due to the small size of the L1 cache.
How L2 Cache Works
Because the L2 cache is significantly smaller than the L3 cache, a processor is able to search for necessary information on the L2 cache in a fraction of the time it takes to search the L3 cache or RAM. However, before the processor can search the L2 cache, it must first search the L1 cache, which is usually only between 8 and 64 KB in size. While the L1 cache is by far the smallest cache in a multi-tier memory cache system and is the easiest to search, the L1 cache does not hold nearly as much information as the L2 and L3 caches. Therefore, most of the frequently used information that a processor needs to conduct its daily activities are found on the L2 cache, while less frequently used information is found on the L3 cache.
The L2 cache is used to increase the speed at which a processor can find information by storing it closer to the processor and storing a relatively large amount of data compared to the L1 cache. While the L2 cache in personal computers is limited in size, the L2 cache of supercomputers, servers, and other commercial systems may be larger or may precede large numbers of caches, depending on the requirements of the particular system.