Cache RAM.

Cache RAM.

CPU CACHE.

1 - The program, through the central processing unit (CPU), requests data or any part of the program code
for use by the CPU.
2 - The RAM cache built into the main circuit of the PC, intercepts the request that is the way to access memory
random. The cache takes the data from the RAM and the CPU sends. A search of the data for the first time can take a few cycles
clock during which the CPU can not do any other job.

3 - The cache also stores a copy of data that have been recorded in the chip high speed memory used only
by him.

4 - Once the cache note that the CPU is idle, it picks up the data or program code from memory addresses
adjacent leads to the addresses of the data that initially requested the program. The cache stores the data on chips
of high-speed memory.

5 - When prompted again that the data is sent to the CPU, the cache checks if such data are already
stored in memory chips at high speed. If so, the cache can send them directly to the CPU without having to
access the slower memory chips. The CPU is less idle time and more time working.

6 - When the CPU wants to change something that is already in memory, the cache first checks if the data to be changed is
chips in high speed. If so, it compares the data it has with the changes and sends data only to those
addresses from main memory that contain data other than those already stored in high-speed chips. This process
is faster than changing the entire block of data.

Note - In addition to the RAM caches found in several PCs based on microprocessors 80386.80486 DX and SX Intel's
486DX processor has 8KB cache within the chip itself. 0 cache works as the internal RAM cache in external
order to further accelerate data movement.

Source: Evolution of Computers