The Importance Of A Cache
Cache is an extremely fast memory used to store instructions that are repeatedly used by the CPU. It accelerates the CPU instruction retrieval process and result in a more efficient system.
Without a cache, the CPU has to retrieve instruction directly from the RAM. Since the RAM operates at a much lower speed than the CPU (18ns to 0.3 ns), the full efficiency of the CPU is not utilized. Its productivity effectively reduced by (18/0.3=60) times. This is not acceptable.
What if we include a cache in the motherboard (known as L2 cache) that has a small memory size but run at twice the speed of the RAM? Things will start to speed up.
To fasten thing up, an even faster cache was built into the CPU. This cache is known as L1 cache. It runs at the same speed as the CPU. Now, the L1 cache caches the L2 cache which in turn caches the memory RAM. The CPU can then operate at its full speed and programs can run more efficiently.
A cache is very expensive, thus it is not advisable to include a big cache into the system. Generally the faster the CPU speed, the bigger the cache you need. A typical system has 64kb of cache. High end CPU such as Intel dual core extreme comes with 4MB cache. This also explains why the dual core CPU is so expensive.
Celeron CPUs are the budget version of Intel chip. They may have the same operating speed as a Pentium4 chip, but are priced very cheaply. The main reason for this is the size of the cache in the chip. A typical Celeron CPU has only 256kb while an Intel Pentium 4 CPU has 2MB cache. This also means that a Celeron CPU operates much slower than a Pentium 4 CPU even though they have the same operating speed.
There are many factors to take note of when building a computer and caching is one of them that cannot be left out. Hopefully this article has given you an insight about the importance of cache.