CPU的运算速度比主内存的读写速度要快得多，这是众所周知的。这样就使得CPU在访问内存时要花相当长的时间来等待内存的数据传递，造成了系统整体性能的下降。为此，在CPU与主内存之间加入了比主内存要快的Cache,以解决系统前后级数据读写速度不匹配的问题。Cache储存了主内存 It is well-known that CPUs operate much faster than main memory reads and writes. This makes the CPU memory access takes quite a long time to wait for the memory data transfer, resulting in a decline in overall system performance. To this end, between the CPU and the main memory than the main memory to add faster Cache, to solve the system before and after the data read and write speed does not match the problem. Cache stores main memory