External Cache

Definition of External Cache

External cache, also known as L2 or Level 2 cache, is a high-speed storage area located outside the CPU but still on the motherboard. This cache temporarily stores frequently accessed data and instructions, enabling the CPU to retrieve them more quickly than from the main memory. By improving retrieval time and data access, external cache enhances the overall performance of the computer.


The phonetic spelling for the keyword “External Cache” is:ɛksˈtɜrnəl kæʃ

Key Takeaways

  1. External caches store frequently accessed data outside of the CPU to reduce latency and improve performance, enabling faster access times compared to the main memory.
  2. There are different levels of external cache, such as L2 and L3, which can be found on the motherboard or within the CPU. They vary in size, access speed, and distance from the CPU.
  3. Effective cache management plays a crucial role in improving system performance, as it optimizes data accessibility and reduces overall processing times.

Importance of External Cache

The term “External Cache” refers to a crucial aspect of computer technology and is important because it greatly enhances a computer’s processing speed and overall performance.

External cache, also known as Level 2 (L2) or Level 3 (L3) cache, is a small, dedicated memory pool situated outside the processor but located closer to the CPU than main system memory.

Since most frequently accessed data or instructions are stored in the external cache, it helps to minimize latency by reducing the time taken to access this information from the main memory.

A larger and faster external cache can result in significant improvements in the efficiency of the processor, making this crucial technology integral to achieving optimal performance in modern computer systems.


External cache, also known as secondary cache or Level 2 (L2) cache, plays a crucial role in enhancing the performance of a computer system. Its primary purpose is to store frequently accessed data and instructions so that the Central Processing Unit (CPU) can retrieve this information more quickly, consequently speeding up processing times.

When the CPU needs to access data, it first checks the external cache memory, which operates at faster speeds than traditional Random Access Memory (RAM). By being able to quickly access commonly used data, the CPU avoids the time-consuming process of searching the slower main memory, thereby increasing efficiency and reducing latency. In most computer systems, external cache works in tandem with the primary (Level 1) cache, which is built directly into the CPU and operates even faster than Level 2 cache.

However, L1 cache is comparatively smaller in size, limiting the amount of stored data. With the addition of an external cache, the system benefits from a larger storage capacity while maintaining rapid access time.

This storage hierarchy, which combines multiple caching levels, allows computer systems to prioritize and manage data in a way that optimizes performance. As technology advances, new cache levels (such as Level 3 and Level 4) have been added to further refine data management processes and maximize system performance.

Examples of External Cache

Intel Smart Cache: Intel’s Smart Cache technology is an example of an external cache utilized in their CPUs. It helps improve the performance and efficiency of their processors by allowing the CPU to access this fast memory cache before accessing the slower system memory (RAM). Intel’s Smart Cache is available in several of their processor series such as Core i7, Core i5, and Core i

L2 and L3 Cache in AMD Ryzen Processors: AMD’s Ryzen processors feature L2 and L3 caches that help improve the overall performance and efficiency of the CPU. The external L2 and L3 caches work together with the internal L1 cache to quickly access and store frequently used data, reducing latency in accessing RAM. The Ryzen processors, including the Ryzen 5, Ryzen 7, and Ryzen 9 series, benefit from these external caches.

Apple’s ARM-based M1 chip: Apple’s M1 chip, an ARM-based system on a chip (SoC) designed for Macs and iPads, includes an integrated cache hierarchy. It features L1, L2, and shared L3 cache, with the shared L3 cache acting as an external cache that enhances performance and efficiency. The M1 chip relies on this cache design to deliver a balance between energy efficiency and powerful performance in devices like the MacBook Air, MacBook Pro, and Mac Mini.

External Cache FAQ

What is an external cache?

An external cache is a hardware component that stores frequently-used data outside the main memory (RAM) of a computer. It allows for faster access to stored data and reduces processing times by minimizing the need for the CPU to access the memory.

What are the benefits of using an external cache?

Using an external cache can improve overall system performance by reducing the time it takes to access or retrieve frequently-used data. It can also reduce the workload on your main memory (RAM) and CPU, leading to better multitasking and smoother operation.

How does an external cache work?

An external cache works by storing and managing frequently-used data in a separate, high-speed storage component. When the CPU needs to access this data, it first checks the external cache. If the data is found in the cache, it is quickly delivered to the CPU, avoiding the need to access the slower main memory.

What types of external cache are available?

There are several types of external cache, the most common types include Level 2 (L2) and Level 3 (L3) caches. These caches act as a bridge between the CPU and main memory, with L2 cache being closer to the CPU and offering faster access times compared to L3 cache. Some systems also utilize solid-state drives (SSDs) as a cache for frequently-accessed files, further improving performance.

How do I know if my system supports an external cache?

To determine if your system supports an external cache, you can check your computer or motherboard’s specifications, or consult the manufacturer’s documentation. Many modern CPUs have built-in L2 and L3 caches, providing additional caching capabilities without the need for external hardware.

Related Technology Terms

  • Cache Memory
  • Memory Hierarchy
  • Level 2 (L2) Cache
  • Data Access Latency
  • Cache Coherency

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