Articles :: A Description of Common Memory :: Motherboards.org

Doc Overclock · 12-29-2000 · Category: Tech-planations

Cache


Cache is commonly referred to as a high speed data storage system with the main use of storing the most frequently accessed data in a buffer, so that these data can be accessed and processed without delay. Because cache needs to be much faster than normal storage devices, it is usually smaller in capacity and more expensive to purchase.

The memory cache is a part of the memory subsystem that stores the most frequently accessed data. It is made of high-speed static RAM (SRAM), instead of the slower and cheaper dynamic RAM (DRAM) used for main memory. Because the SRAM memory chips are more expensive and much larger in size, the cache memory size is always limited to within a few KB. Memory caching is effective because most programs access the same data or instructions over and over. By keeping as much of this information as possible in SRAM, the computer avoids accessing the slower DRAM.

Sometimes the cache memory is built into the microprocessor, as with most x86 processors today. Currently, the cache memory is usually categorized in different levels. The level 1 (L1) cache is the fastest and smallest in capacity, normally between 16KB and 32KB, the level 2 (L2) cache is the second fastest and a bit larger in capacity, normally between 128KB to 512KB for PC usage, and as high as 2MB for server applications.

Contents

  1. SDRAM
  2. RDRAM
  3. DDR
  4. Flash ROM
  5. Cache