What is Level 3 Cache (L3 Cache)?
A level 3 (L3) cache is a special cache used by the CPU and is usually built on the motherboard and in certain special processors within the CPU module itself. It works in conjunction with the L1 and L2 cache to improve computer performance by preventing bottlenecks due to the long cycle of getting and executing. The L3 cache forwards information to the L2 cache, which then forwards information to the L1 cache. In general, its memory performance is slower compared to the L2 cache, but still faster than the main memory (RAM).
The L3 cache is usually installed on the motherboard between the main memory (RAM) and the L1 and L2 caches of the processor module. This acts as another bridge for storing information such as processor instructions and frequently used data to avoid bottlenecks that result from fetching this data from main memory. In short, today's L3 cache is what the L2 cache was before it was built into the processor module itself.
The CPU looks for information it needs from L1 to the L3 cache. If it doesn't find this information in L1, it looks to L2 and then to L3, the largest and slowest in the group. The purpose of the L3 depends on the design of the CPU. In some cases the L3 contains copies of instructions that are often used by multiple cores that share it. Most modern CPUs have built-in L1 and L2 caches per core and share a single L3 cache on the motherboard, while other designs have the L3 on the CPU chip itself.