What is L2 Cache
Cache Memory acts as a high speed buffer between the RAM and CPU. Cache RAM operates at higher clock frequencies than normal RAM. This allows the data to be read more quickly from the cache than the main memory.
Cache memory functions as a “near store” of RAM i.e. these are the stores which the CPU can always be supplied from. There are at least two close stores which are called Level 1, Level 2 cache (Level 3 cache is also sometimes there e.g. in Intel Itanium processors, Level 3 cache is there). The cache memory ensures that data is constantly fetched from the RAM so that CPU does not sit idle.
The Level 2 cache is much bigger than the Level 1 cache. It can be 256, 512 or 1024 KB. Level 2 Cache is slower than the Level 1 cache but is still much faster than the normal RAM. Level 2 Cache is used to constantly read the large quantities of data from thee RAM and it makes the data available to the L1 cache which provides it further to the CPU.
The L2 cache was placed outside the RAM chip i.e. either on the motherboard or on a special module together with CPU.
As the development in the technology, the L2 cache is now placed inside the processor chip. This increases the productivity as it makes it possible to function much better in relation to the L1 cache. In processors such as Pentium Pro, Celeron (later generation), Pentium III, Pentium 4 and so on, the L2 cache is placed inside the processor chip only.
The normal RAM is a dynamic one. The integrated cache is made using SRAM (i.e. Static RAM) and 6 or more transistors are needed to make 1 bit of SRAM. Thus only 512 KB of L2 cache would require more than 24 million transistors. It has become feasible to integrate these much millions of transistor only with the help of this fine process technology.
Caches can be used in different ways. For e.g. – Intel and AMD have saved on L2 cache for making economical products. But better the cache, the more efficient the CPU will be and will deliver high performance. In the future, CPU’s can be seen with more L2 cache and more advanced memory management.