Definition
Level 3 cache is a cache memory that computer processors use to temporarily store frequently accessed instructions and data.
It is located between the CPU and RAM and is the third tier in the multi-level cache hierarchy, after L1 and L2 caches.
How Does an L3 Cache Function?
Unlike the L1 and L2 cache types, the L3 type stores more data but is slightly slower. When the CPU searches for data, it first checks in the L1 and then in the L2, and if it cannot find the data in either of these two, it will look in the L3 cache.
If the data is available in the L3 cache, the processor draws it directly, eliminating the need to access it, which would otherwise hinder performance.
Evolution of Multi-level Caches
As computing needs grew and processors advanced, the CPU speeds and main memory access times increased. Multi-level caching systems were introduced to tackle this challenge. L3 cache was added to L1 and L2 to improve performance even further. It is precious in multi-core processors, where it serves as a shared cache for every core.