L1välimuistin

L1 välimuisti, also known as Level 1 cache or L1 cache, is the smallest and fastest type of memory found in a computer's central processing unit (CPU). It is located directly on the CPU core itself, allowing for extremely quick access to frequently used data and instructions. The purpose of the L1 cache is to reduce the time the CPU spends waiting for data to be fetched from slower main memory (RAM).

The L1 cache is typically divided into two parts: the instruction cache and the data cache. The instruction cache stores recently executed or soon-to-be-executed instructions, while the data cache stores data that the CPU is actively working with. This division helps to optimize performance by allowing the CPU to fetch instructions and data in parallel.

Because of its proximity to the CPU core and its small size, the L1 cache has a very low latency, meaning it takes minimal time to retrieve information. However, its limited capacity means it can only hold a small amount of data. When the CPU needs data that is not in the L1 cache, it must access the next level of cache (L2 cache) or main memory, which are progressively slower. The effectiveness of the L1 cache is a significant factor in overall CPU performance.