There are many different types of cache memory to choose from. Below some of the most popular described.

Async SRAM (ASRAM)
ASRAM is a very old type of cache memory. It is called asynchronous RAM because it is not synchronized with the system clock, as most memory now is. Because of this, data takes longer to be recalled.

Pipeline Burst (PB) SRAM
PB SRAM pipelines certain memory content before it is requested. That way, when it is requested, it can be accessed almost instantaneously. PB SRAM works well with bus speeds of 75MHz and up, and although it is not synchronized, it may be slightly better than Sync SRAM.

Sync SRAM or Sync Burst SRAM
This type of SRAM is synchronized with either the system clock or the cache bus clock. This allows it to be synchronized with any device that accesses it more easily, thereby reducing access waiting time.