The system memory, or RAM, is where the data is stored during the processor is working on it or after it has completed calculating. Memory performance is important to a speedy system. Slow memory can slow down the system and decrease the processor’s efficiency. 2 types of memory are used in a system: cache and main memory.

Cache

The main memory isn’t the only place from which the processor gets information. It also uses its own banks of storage, known as Level 1 (L1) and Level 2 (L2) cache. As the cache is right on the processor’s die, the processor can use it faster than the main memory.

Data is swapped from the main memory to the cache by the cache controller. The cache controller attempts to guess what data the processor requires next. If the processor prompts for that data, it’s instantly presented and the processor goes to work on it. This is known as a cache hit. When the processor prompts for data that’s not loaded into cache, it’s known as a cache miss.Al-though RAM’s getting faster, it still doesn’t run as fast as the processor. This is why cache hits are very important to the speed of the system.

L2 cache varies from L1 cache in many ways. First, it’s bigger: latest processors have 256K or 512K of L2 cache, and only 64K of L1 cache. Second, it only takes a few nanoseconds to reach L2 cache. L2 cache is on the die with latest processors, but it didn’t used to be; in earlier computers, it’s on the motherboard, individual from main memory and in place of running at the processor core speed like L1 and latest L2 cache, it runs at the speed of the FSB.

Cache hits are very important to the speedy performance of a processor. It’s always good to have the required information right on the die rather than on copying it from the main memory. No matter how quick the FSB or the memory of the PC, it can’t beat the immediate completion of a cache hit.

One can’t upgrade the processor’s cache, because the cache is included on the chip itself. In previous versions, cache came in the form of socketed chips on the motherboard and can be included when required. Cache has been shifted to the processor die.