What is Cache Memory?

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  • Written By: R. Kayne
  • Edited By: Niki Foster
  • Last Modified Date: 25 January 2020
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Cache (pronounced cash) memory is extremely fast memory that is built into a computer’s central processing unit (CPU), or located next to it on a separate chip. The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cache memory is that the CPU does not have to use the motherboard’s system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard’s capability. The CPU can process data much faster by avoiding the bottleneck created by the system bus.

As it happens, once most programs are open and running, they use very few resources. When these resources are kept in cache, programs can operate more quickly and efficiently. All else being equal, cache is so effective in system performance that a computer running a fast CPU with little cache can have lower benchmarks than a system running a somewhat slower CPU with more cache. Cache built into the CPU itself is referred to as Level 1 (L1) cache. Cache that resides on a separate chip next to the CPU is called Level 2 (L2) cache. Some CPUs have both L1 and L2 cache built-in and designate the separate cache chip as Level 3 (L3) cache.


Cache that is built into the CPU is faster than separate cache, running at the speed of the microprocessor itself. However, separate cache is still roughly twice as fast as Random Access Memory (RAM). Cache is more expensive than RAM, but it is well worth getting a CPU and motherboard with built-in cache in order to maximize system performance.

Disk caching applies the same principle to the hard disk that memory caching applies to the CPU. Frequently accessed hard disk data is stored in a separate segment of RAM in order to avoid having to retrieve it from the hard disk over and over. In this case, RAM is faster than the platter technology used in conventional hard disks. This situation will change, however, as hybrid hard disks become ubiquitous. These disks have built-in flash memory caches. Eventually, hard drives will be 100% flash drives, eliminating the need for RAM disk caching, as flash memory is faster than RAM.


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Discuss this Article

Post 88

Where is cache memory located with respect to a Central Processing Unit and main memory?

Post 85

That was a precise and excellent explanation of cache.

- vinod

Post 82

very helpful and precise. hope you will explain all parts of the computer like this one.

Post 81

this cache memory is built right into the processor.

Post 80

then what is the difference between SRAM and DRAM?

Adaickalavan Palamneeyappan
Post 76

Clear information. Good!

Post 72

this is very nice and clear information. thanks for you who has written this.

Post 67

it is primary or secondary?

Post 66

which one these is on chip memory?

a.main memory


Post 65

what is the main role of cache memory and where is it?

Post 63

I love wise geek. Thanks for the info on cache. I wasn't even pronouncing it right.

Post 62

Thanks for sharing your knowledge.

Post 59

can you help me with some details about cache? and some information?

Post 56

thanks, just what i needed - short, clean and simple explanation.

Post 55

Excellent and precise piece of information. Thanks.


Post 54

I can say only thanks. i got what i needed.

Post 53

I just want to ask: what are the various types of i/o buses and what are their functions?

Post 49

I want to know where's the cache memory is located? Is it in RAM?

Post 48

Very nice concept. Simple and short. Thanks.

Post 47

should a cache ever be cleared?

Post 46

Really crisp and clear definition. Was searching Web and was getting idea which was not penetrating my dumb head. It is really awesome. Thanks for it. Satya

Post 44

flash memory is not faster than RAM. Get your facts straight.

Post 41

very helpful and precise. hope you will explain all parts of the computer like this one. thanks

Post 40

What's the general size allocated for cache memory?

Post 39

it's simply awesome.

Post 38

Super, dude. Very short and clear.

Post 37

short and sweet. Thanks.

Post 36

what is the performance of the system when it has more cache?

Post 35

Thanks for the info, short but to the point and clear.

Post 34

what is your prediction when hdd will be 100 percent flash? What are your predictions on when common cpu's will reach 1gb/10gb/100gb of L1?

Post 31

Well informed. good job Pro

Post 30

Thanks a lot. This post is extremely superb. The explanation is really really cool.

Post 28

Please help me. MY L2 cache's value is 0 when it is read by my TuneUp Utilities... but by reading it with CPU-Z it has its values.

Post 27

how can you rank speed from primary memory and secondary memory?

Post 26

thank you for giving the good answer,

but i just wanted to how many levels are there in a cache.

Post 24

Simply superb!

Post 23

Thank you, this article was very helpful. I'm doing A Level IT, and I found it extremely useful!

Post 22

"if i clean my cache will this fix my youtube? the sound works but the picture freezes." ROFL

Post 20

Marvelous article. Just continue to write this type of articles. Thanks.

Post 19

if i clean my cache will this fix my youtube? the sound works but the picture freezes.

Post 18

Great effort. Any computer user could understand it. hats off.

Post 17

The way of explanation is excellent.

Post 16

does intel 8086 has a cache memory???? answer me please?? thanks.

Post 15

It was excellent article. i want to ask about the difference between the role of Ram and cache in mother board

Post 14

cache memory is made of?

From which processor cache started? What is the speed and width?

Post 11

Fantastic answer. It explains it so well!

Post 10

It would be better to have 2MB cache and 1GB RAM as Cache is generally a lot faster (2-3 times) than RAM.

Post 9

Basic Factors to consider before buying a new computer are:

1. What will it be used for? This will determine whether or not you need a powerful processor, extra RAM or overall performance capabilities.

2. Reliability. Will all the components work correctly and efficiently?

3. Will it require space for future improvements? If in the future you wish to upgrade your pc, you will need to have extra space such as extra PCI slots and drive bays.

4. Spacial Awareness. How much room have you got to put your PC? Do you need a small, more compact PC or can you manage with a big pc that takes up a lot of space?

Post 6

What are the basic factors that I should consider before I buy a new computer?

Post 5

does cache memory prevent the processor from being idle? if yes then how?

Post 3

I have a similar it better to go with 1mb L2 cache and 1gb ram or 2mb cache and 1gb ram?

Post 1

hi i just wanted to ask if there is a big difference in performance between a 1mb & 2mb cache and any way in which i would feel the difference when im using the laptop? thnx a lot

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