What is an L2 cache?

With the latest computers, the L2 cache size shows up as part of the technical specifications of every PC. So, what is it?

Computers have DRAM(Dynamic Random Access Memory) chips in them. We all know that reading from DRAM is much faster than reading from Disk(Paging). There’s another level of storage that modern computers use in order to retrieve data very quickly. These are the Level caches on the CPU. Specifically Level 1 (L1 cache) and Level 2 (L2 cache).

Generally, the data that is retrieved most often is stored directly in the L1 cache which offers the most quickest path of data retrieval,but the size of this cache is smaller than that of the L2.
Example : Instructions in a loop that execute repeatedly are stored in L1 cache. The next level of CPU storage is the L2, slightly slower than the L1.

So, when the processor has to execute some instruction, first it looks in it’s own data registry, then the L1 cache and then the L2 cache. If the instructions aren’t found on one of these caches, it next goes to the DRAM.

What size or how much L2 do i need and does it boost performance?

Well, it depends on the kind of application that will be run on your machine. If you plan to use processor intensive applications like 3D design softwares, Games etc., it’s better that have higher L2 for better performance. Processors with higher cache memory are expensive. So, it’s best know the end user application requirement before making such an investement. Highter memory can definitely boost performance. Read this article to find the performance of different sizes of caches : CPU chipset performance