What is the Difference Between L1 L2 and L3 Cache

The main difference between L1 L2 and L3 cache is that L1 cache is the fastest cache memory and L3 cache is the slowest cache memory while L2 cache is slower than L1 cache but faster than L3 cache.

Cache is a fast memory in the computer. It holds frequently used data by the CPU. The RAM or the primary memory is fast, but the cache memory is faster than RAM. The CPU first checks the cache to find the required data. It works as the middle layer between the CPU and RAM to provide data faster to the CPU. Therefore, it helps to increase the computation speed of the device. There are three types of cache as L1, L2, and L3.

Key Areas Covered

1. What is L1 Cache
      – Definition, Functionality
2. What is L2 Cache
     – Definition, Functionality
3. What is L3 Cache
     – Definition, Functionality
4. What is the Difference Between L1 L2 and L3 Cache
     – Comparison of Key Differences

Key Terms

Cache Memory, L1 Cache, L2 Cache, L3 Cache

Difference Between L1 L2 and L3 Cache - Comparison Summary

What is L1 Cache

L1 cache is the level 1 cache memory. We also call it the primary cache. It operates at the same speed as the CPU. Also, it is the fastest cache among all other caches. Moreover, it is smaller than other caches, which are L2 and L3. Furthermore, each core in the CPU has their own L1 cache memory.

What is L2 Cache

L2 cache is the level 2 cache. It stores the data that is not stored in the L1 cache. In other words, if the CPU cannot find the data it is looking for in the L1 cache, it checks the L2 cache. Furthermore, L2 cache is larger than L1 cache but smaller than L3 cache. Each code in the CPU has their own L2 cache memory.

What is L3 Cache

L3 cache is the level 3 cache. It stores data that is not stored in L1 and L2 cache. In other words, if the CPU cannot find the data it is looking for in L1 and L2 cache, it checks L3 cache. Moreover, L3 cache is the largest among all caches. Also, all the cores in the CPU share the same L3 cache memory.

Difference Between L1 L2 and L3 Cache

First, the CPU checks the L1 cache for data. If it is not available, it will check L2 cache. If the data is not available, it will check L3 cache, and if the data is not available in L3, it will check the RAM.

Difference Between L1 L2 and L3 Cache

Definition

L1 cache is a cache memory that is directly built into the processor and is used to store the CPU’s recently accessed information. In contrast, L2 cache is a cache memory that is located outside and separated from the CPU chip core, although it is found on the same CPU chip package. Meanwhile, L3 cache is a cache memory that is used by the CPU and is usually built onto the motherboard within the CPU module itself. Thus, these definitions contain the basic difference between L1 L2 and L3 cache.

Size

Size is also an important difference between L1 L2 and L3 cache. L1 cache is the smallest cache while the L3 cache is the largest cache. L2 cache is larger than L1 but smaller than L3 cache. 

Synonyms

L1 cache is called level 1 or primary or internal cache while L2 cache is called level 2, secondary or external cache and L3 cache is called level 3 or external cache.

Speed

Speed is another significant difference between L1 L2 and L3 cache. L1 cache is the fastest cache and L3 cache is the slowest cache while  L2 cache is slower than L1 but faster than L3 cache.

Association with CPU cores

Each core in the CPU has their own L1 cache memory while each code in the CPU has their own L2 cache memory. However, all the cores in the CPU share the same L3 cache memory. Hence, this is another difference between L1 L2 and L3 cache.

Conclusion

Cache is a component in the computer that stores data so that future requests for the data can be served faster. There are three types of Cache as L1, L2, and L3. The difference between L1 L2 and L3 cache is that the L1 cache is the fastest cache and L3 cache is the slowest cache while the L2 cache is slower than L1 but faster than L3 cache.

Reference:

1. CPU Cache Explained – What Is Cache Memory?, PowerCert Animated Videos, 27 Nov. 2016, Available here.

Image Courtesy:

1. “ذاكرة الكاش” By Ammar soud91 – Own work (CC BY-SA 3.0) via Commons Wikimedia

About the Author: Lithmee

Lithmee holds a Bachelor of Science degree in Computer Systems Engineering and is reading for her Master’s degree in Computer Science. She is passionate about sharing her knowldge in the areas of programming, data science, and computer systems.

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