What Is a PC Cache? A Basic Definition

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A CPU cache (pronounced cash) is found in the processor and holds data a PC frequently uses so that the processor can access it quickly to perform repetitive tasks more rapidly. A CPU usually has three levels of caches and 1-4MB of total memory.

A cache can perform rapid writing and rewriting of data, thanks to its being made up of SRAM (static RAM) chips instead of DRAM (dynamic ram) chips. This is because SRAM chips access data faster than DRAM. Also, because the cache memory is right on the CPU die, the data doesn't have to travel all the way over from the DRAM chips or storage drive.

For consumer CPUs, there are three different types of cache: 

  • L1 - the fastest but smallest
  • L2 - the second fastest and second smallest
  • L3 - the slowest and biggest

Note that when buying a CPU, cache isn’t that important because it’s hard to correlate a CPU’s cache size with your real-life experience.

This article is part of the Tom's Hardware Glossary.

Further reading:

Scharon Harding
Scharon Harding

Scharon Harding has a special affinity for gaming peripherals (especially monitors), laptops and virtual reality. Previously, she covered business technology, including hardware, software, cyber security, cloud and other IT happenings, at Channelnomics, with bylines at CRN UK.

3 Comments Comment from the forums
  • Rick C-137
    This article is not very informative and also seems false. The article says "when buying a CPU, cache isn't that important because it's hard to correlate a CPU's cache size with your real life experience."

    I say this is false because:
    read the Tom's hardware review of the 5800x3D which is literally the same CPU as the 5800 but with more cache; it shows a clear correlation between cache and gaming performance.
    hardware unboxed did a video disabling cores of an Intel i9 to show that even on Intel a small number of cores, but with the i9's amount of cache out performed i3s and i5s with the same number of cures but less cache.

    It would be helpful if the article provided a typical range in the differences in latency between different levels of cache and memory. On AMD 5000 series I believe it is a factor is 10 in comparing L3 with DDR4
    Reply
  • kanewolf
    Guest said:
    What does a PC cache do? The meaning of a PC cache explained.

    What Is a PC Cache? A Basic Definition : Read more
    In the most general definition, a cache is temporary storage. It might be RAM built into a CPU which temporarily stores data from main memory. It might be system RAM which temporarily stores data from disk. It might be your router, which temporarily stores DNS lookup data pulled in from the internet.
    Reply
  • ex_bubblehead
    This was written 4 years ago. No need to be commenting now.
    Reply