Cache Memory is the fastest memory among the given options.

Cache Memory is a small, high-speed memory that is located closer to the CPU (Central Processing Unit) compared to other types of memory. It is designed to store frequently accessed data and instructions, providing fast access to the CPU. Cache memory acts as a buffer between the CPU and the main memory, reducing the time required to fetch data from the main memory.

Key Points:
- Role: Cache memory plays a crucial role in improving the performance of the computer system by reducing the average time required to access data.
- Speed: Cache memory operates at a much higher speed compared to other types of memory, such as secondary memory, auxiliary memory, and virtual memory.
- Proximity to CPU: Cache memory is located directly on the CPU chip or in close proximity to it. This closeness allows for faster access and retrieval of data and instructions.
- Size: Cache memory is relatively smaller in size compared to main memory. It is designed to hold a subset of frequently accessed data and instructions, which can be quickly retrieved by the CPU.
- Levels: Cache memory is organized into multiple levels, such as L1, L2, and L3 cache. L1 cache is the closest and fastest, while L3 cache is larger and slower.
- Cache Hierarchy: The cache hierarchy ensures that the most frequently accessed data is stored in the fastest cache level, while less frequently accessed data is stored in higher-level caches or the main memory.
- Cache Hit vs. Cache Miss: When the CPU requests data, if it is found in the cache memory, it is referred to as a cache hit, resulting in faster access. If the data is not found in the cache and needs to be retrieved from the main memory, it is referred to as a cache miss, resulting in slower access.
- Cache Coherency: Cache memory also maintains cache coherency, ensuring that multiple cache copies of the same data are synchronized and consistent.

In conclusion, cache memory is the fastest memory among the given options due to its proximity to the CPU, high-speed access, and efficient caching algorithms. It plays a critical role in improving the overall performance of the computer system.