What is CACHE MEMORY ?

You may have heard about CACHE MEMORY at two places that are while seeing a specification of a processor & while seeing app info in  settings on a android device. These two CACHE MEMORY are completely different things. So don’t confuse between them. Here in this post we will discuss about both type of CACHE MEMORY. First we will see about CACHE MEMORY of a app as it is little bit easier to understand then we will see about CACHE MEMORY of processors. So let’s begin.

What is CACHE MEMORY of an app ?

You may have already visited APP INFO in your SETTINGS on any smart phone device & you may have noticed a term CACHE MEMORY & you may be wondering what is this using this much space & even if you clear your CACHE MEMORY then too it will be same again after some time.

cache memory of app

You may be using some of the apps like Facebook ,  Instagram , google maps. So sometime apps need to store some of the information temporarily so for this they use CACHE MEMORY. You may have noticed that as soon as you open gallery in your phone you are able to see small thumbnails of taken pictures in your gallery. So these thumbnails are stored in CACHE MEMORY. If thumbnails are not stored in CACHE MEMORY than every time you will open gallery than processor will have to make new thumbnails again & again for you. So this process will consume more power & always put load on processor to carry out same task every time. So to avoid these situation thumbnails are stored in CACHE MEMORY of a app.

Similarly If you use Facebook you are able to see some of pictures & video as soon as you open Facebook. So these are stored in CACHE MEMORY temporarily. So every time it don’t have to use your data to load same picture & video frequently. Almost all apps have their own respective CACHE MEMORY.

cache memory of a app

Should I clear CACHE of an app ?

Sometime CACHE MEMORY of some large apps can even reach to 700 MB. So you might be thinking that it is better to free up this space by clearing CACHE. But my recommendation is that you should try not to clear cache as after sometime it will be in the same position & your processor will have to carry out same task again. So it will consume more energy thus affecting the battery. If you have some serious storage issue then you can give clearing CACHE a try but mostly ignore the CACHE MEMORY.

Clearing CACHE for no reason makes no sense as CACHE MEMORY helps to run device smoothly. You can clear CACHE if CACHE MEMORY had become really huge i.e. greater than 1.5 GB or your app had started malfunctioning.

Now forget about this here only. Because the CACHE MEMORY which we are going to discuss further is a completely different thing.

What is CACHE MEMORY of a processor ?

First let me tell you that there are basically three types of memory in a computing system:

  1. HARD DRIVE 
  2. RAM-RANDOM ACCESS MEMORY
  3. CACHE MEMORY

To know about hard drive click on the link given below:

Difference between HDD & SSD explained

cache memory of a processor

CACHE MEMORY is the fastest memory. As it uses electrical signals to read & write data this concept is called FLASH MEMORY. CACHE MEMORY do not have any moving part unlike HDD. But storing capacity of CACHE MEMORY is very very less compared to RAM also.

To know about RAM click on the link given below:

What is RAM ? DDR2 ,DDR3, DDR4 explained.

Types of CACHE MEMORY:

Usually there are 3 types of CACHE MEMORY in a processor : 

  1. L 1- LEVEL 1 CACHE
  2. L 2- LEVEL 2 CACHE
  3. L 3- LEVEL 3 CACHE

Basically every core of a processor have their own individual respective L 1 & L 2  CACHE MEMORY.  While L 3 CACHE is commonly shared among all the cores of a processor. L 1 cache is fastest among all the CACHE MEMORY & L 2 is bit slower than the L 1 cache and usually they are placed in processor only. So the data exchange between L 1,L 2 & core of processor is lightning fast. Some time it may be possible that L 2 is situated outside the processor but then too it is tried to keep the minimum distance between CACHE & core. CACHE & core of a processor are always connected with ultra high speed bus to transfer data. L 3 is a separated memory it is compulsorily situated outside the processor. CACHE MEMORY are lot faster than the RAM.

cache memory of a processor

To know about cores of a processor click on the link given below:

What are CORES in a processor/CPU ?

CACHE MEMORY explained with a example:

Now assume that you are sitting in your office. Your file racks & cabinets are your hard drive. Your desk is your RAM & you are a processor. The drawers made in the table are the CACHE MEMORY. Drawers are small but they are quickly & easily accessible to you as they are very near. So whenever you have to work on file you have to call that file from cabinet to your desk this is same as RAM fetching file from HARD DRIVE. Now you will start working on that file similar to PROCESSOR processing files fetched from RAM. Your drawer contain punching machine, pen, stapler you will need these basic things every time you work on a file. Similarly important instruction which is needed to process a file by a core every now & then is stored in cache memory.

Now assume that your pen stopped working then you have to get up & bring new pen this will cause delay in your work.  It is similar to while a processor need some basic instruction from cache to process a file but due to some reason it was not found there. Then it will have to go to main HARD DRIVE to search for necessary instruction. So it will cause some delay in the processing of a file. So this delay is basically termed as LATENCY OF A CACHE.

cache memory of a processor

How CACHE MEMORY helps PROCESSOR ?

A processor always first look in the CACHE MEMORY for necessary data & instruction. If it is found there by processor then the work is carried out easily with very high speed. If it is not found there then processor will look in RAM.  If it is not present there also then it will fetch necessary information from hard drive through RAM so this process consume lot of time. Due to this CACHE LATENCY occur. In short CACHE store very important general information that is frequently needed by processor for computing. CACHE MEMORY usually nowadays range from 2 MB to 40 MB. It may seem small to you. But even 12 MB is really huge for CACHE MEMORY to carry out daily task for a ordinary user.

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