What Is Cached Data and Should You Keep it or Clear it?

Devin Pickell
Devin Pickell  |  May 31, 2019

Not sure if you’ve noticed, but opening an app or visiting a website for the first time can take a while.

Okay, a “while” may be extreme, but those extra few seconds of loading time do matter to us when surfing the web or scrolling through our apps.

Although, it isn’t a coincidence why this happens. It’s mainly due to our devices not having cached data for a particular app or website.

If you’re not quite sure what cached data is, let me explain.

What is cached data?

With every app opened or website visited comes a bartering of information.

The user gets to enjoy content in exchange for location info, which device they’re using, which browser they’re using, time spent on pages, and other user behaviors.

Then there’s cached data.

Laptops, tablets, smartphones, it doesn’t matter. All our devices have some level of reserved space to store this type of data for quick access.

How does cached data work?

For cached data to be stored for re-access, there needs to be memory. On a more technical side, the cache is very high up on the hierarchy of computer memory. Here’s a visual of this hierarchy for reference:

hierarchy of computer memory

You can see just below the CPU register – the small building blocks of the computer processor – are a few levels of cache memory.

  • L1, or level 1, is the primary level of cache built into the microprocessing chip.
  • L2 and L3, or level 2 and 3, are the secondary level of cache which feeds the L1. It is slower than L1 by nanoseconds.

Cache memory has extremely low latency, meaning it can be accessed very quickly. You can test this by opening a new app or visiting a website you’ve never been to before, then revisit it, and compare the speeds. Hint: Your second time around should be noticeably faster.

The flip side to low latency means not much memory can be stored. This is why small-sized files like web text and images are stored in the cache.

Is cached data important?

Cached data isn’t inherently important, as it’s only considered “temporary storage.” However, it does exist to improve the user experience.

On-page elements like images, videos, and even text take some time to load. When this data is cached, we can reopen the app or revisit the page with confidence that it won’t take anywhere near as much time.

Cache memory also saves states. For example, if I close my Twitter app and reopen it 10 minutes later, I’ll be able to scroll down and see posts that were previously loaded. Without cache, everything would need to reload.

Should I clear my cache?

So, if cached data isn’t that important, is it safe to erase? Well, that depends.

If you find your mobile device memory being drained from cached data, then you should probably clear it. After all, cached data isn’t vital to the performance of an app or website, it just means the files on it will have to be reloaded.

Although, constantly clearing your cache isn’t a permanent solution, since you’ll eventually be reopening apps and revisiting websites at some point. The data will be re-cached and the cycle will continue.

If you’re that strapped for memory, consider deleting old text messages, images, or video files on your device. It’s also worth looking into cloud-based file storage and sharing software like Google Drive or Dropbox if you want to hold on to your files. These options typically offer a free amount of cloud space.

How to clear cached data

If you’re all-in on clearing your cache, here’s how to do so on iOS devices.

Go to Settings > General > iPhone Storage.

From here, you have a few options. Your first option is to clear the entire cache of apps you hardly or never use. This is under the recommendation Offload Unused Apps. The term “offload” is just iOS’ fancy phrase for clearing the cache.

offload unused apps on iOS

The second option is to scroll down and tap on individual apps with lots of cached data on your device. How can you tell this? Apple will list these apps from the highest usage of memory to lowest.

clear cached data on iOS

Simply offload the individual app to free up some temporary space on your device.

Tip: Clearing the cache simply clears temporary files. It won't erase login credentials, downloaded files, or custom settings.

The verdict

You now have a pretty in-depth understanding of what cached data is, where it’s stored, and it’s importance when it comes to device performance.

My verdict?

It’s really not bad to clear your cached data every now and then. Some refer to this data as “junk files,” meaning it just sits and piles up on your device. Clearing the cache helps keep things clean, but don’t rely on it as a solid method for making new space.

Devin Pickell
Author

Devin Pickell

Devin is a Content Marketing Specialist at G2 Crowd writing about data, analytics, and digital marketing. Prior to G2, he helped scale early-stage startups out of Chicago's booming tech scene. Outside of work, he enjoys watching his beloved Cubs, playing baseball, and gaming.