Cache memory is a small and fast memory which is located between the CPU and main memory. It is accessed at a very speed than the system memory. As a result, the programs which access the same data or instruction over and over run faster. The CPU does not have to navigate to the main memory to get the data. It will first access the cache memory to find the data.
CPU first check on the cache to find the data, if the data is not found then it proceeds to the system memory. This result in faster access to the data in the cache. But, it will be lagging if the data is not found in the cache and on the system memory. This can be countered with the modern hardware and better cache design. The time taken to traverse the cache is very less as compared to the whole RAM as it is the small and fast memory.
Cache levels describe to the electronic pathways and connecting circuits via which cache memory is connected to the CPU. They also specify the physical closeness of cache memory to CPU. Most of the modern computers use 2 or 3 cache levels so the processor does not have to wait for a longer time for information from the memory.
Different Types of Cache Levels are:
L1 – L1 cache is referred to the cache which is assembled in the processor. This is the fastest cache in the computer. This cache is also known as the primary or internal cache. The common size of this type of cache memory is 8 KB to 64 KB.
L2 – New CPUs like from Pentium pro onwards generally incorporate the L2 cache directly on the processor chip. Earlier, the L2 cache was situated outside the processor i.e. commonly present on the motherboard. The common size of this type of cache memory is 64KB to 8 MB.
L3 – Today, all modern processors have the L2 cache on them, thus the cache on the motherboard is referred to as the L3 cache. Often only high-end workstations and servers require L3 cache. L3 has been part of the CPU or externally installed near the CPU on the motherboard. It comes in many size and speeds.