Why Do SSDs Slow Down When Full?

Solid-state drives are storage devices that have replaced hard drives in most laptops and computers nowadays. Their main advantages are the lack of mechanical parts and increased capacity. However, SSDs can also get full if you store a lot of information, so what does this mean for your device?

SSDs slow down when full because they require more time to store data in their blocks. There are no empty blocks when the SSD is full, so it needs to modify the data before storing it, which takes time. This issue can affect your computer and your programs. 

In the rest of this article, I’ll explain why SSDs slow down when full and how much free space you should leave to avoid these issues. Additionally, I’ll show you how to fix this problem in a few different ways.

Why Do SSDs Slow Down When Full?

Why do SSDs slow down when full?

Should You Leave Some Space on Your SSD?

One of the reasons why SSDs are superior to hard drives is the fact that they are generally faster. When you have an SSD, your device can work better and faster than it would if you were using an HDD of the same capacity. 

You should leave some space on your SSD as it can slow down when full. Although these devices work better than HDDs, you should leave some free space on this device to ensure that it will work as fast as possible. 

Indeed, your SSD will always perform better than a hard drive, but if it’s completely full, you may get more or less the same performance, if not a slower one. Ensuring your SSD is never full can help you maintain a consistently fast performance.

Why SSDs Slow Down

To understand why SSDs slow down when they get full, you need to have an idea of how they work. 

Solid-state drives are made of small units called blocks, which store information when the device writes information on them. The more data you store, the fewer empty blocks are available on the drive. An almost full SSD typically doesn’t have any empty blocks, just partially filled ones.

If you try to write a file on this full SSD, the device won’t be able to use partially empty blocks directly. This is because it would need to destroy the data that is already inside the block before writing new files.

To avoid this issue, SSDs put the existing content into the cache inside a block and modify it using the new data. Afterward, this modified content is written back to the block.

Understandably, this process takes considerable time, especially if you’re writing multiple files to your SSD.

As a result, the SSD slows down a lot, which will be noticeable in the overall performance of your computer or laptop, as I will describe below. Allowing your SSD to have empty blocks could avoid these issues.

What Does a Slow SSD Mean for Your Device?

The Solid-state drive is a crucial part of your device. This drive stores your operating system, your apps and programs, and everything else you want to save on your computer. Pictures, videos, documents, and data sets, are all stored in your internal SSD.

When your SSD is working normally, you can work on your device as usual and won’t notice how long it takes to open a file or copy and paste an image. However, once the SSD gets full and slows down, you may start to notice a few different issues:  

  • It may take longer to boot your computer because your operating system will slow down.
  • Your apps or programs will also take more time to open and register your commands.
  • You may need more time to open pictures or videos on your computer.
  • It may take a relatively long time to copy and paste a file.
  • Your programs may often freeze.
  • It will not be possible to store large files.
  • Complex programs may not even be able to load at all.
  • Sometimes, your device may freeze as a result of your slow SSD.
  • You may see the blue screen of death.
  • You can’t update your operating system.

As you can see, a slow SSD can make it incredibly hard for you to continue work as usual because every step of every process will take longer than it used to. If you work with especially complicated programs, you need a smooth and fast performance, so a full SSD would be unacceptable.

What To Do When Your SSD Slowing Down

When you notice some of the signs I have mentioned above, you should check the capacity of your SSD to see if it’s full and is causing these issues. To check the capacity of your Windows device, you can follow these steps:

  1. Go to This PC on your desktop or find it using File Explorer.
  2. Find Devices and drives.
  3. You will get a list of all the storage devices connected to your device; check out the status bar to see if your SSD is nearly full.

To check out the available space left on your Mac, you can follow the instructions below:

  1. Go to the Apple menu on the upper left corner of your screen.
  2. Select the first option on the menu: About This Mac.
  3. A small window will appear with some basic information; select More Info.
  4. In the new window that will appear, scroll down to find Storage.
  5. Choose Storage Settings, and you will see the available space on your SSD.

If you see that your SSD is almost full, you can try a few different ways of lightening the load by deleting unnecessary data. 

Empty the Recycling Bin

For instance, you can empty your recycling bin to get rid of deleted files that are still taking up a considerable amount of space on your device. All you need to do is right-click on the bin icon and then select Empty Bin or Empty Recycling Bin, depending on what type of device you’re using.

In some cases, you may want to hang on to certain deleted files just in case. You can remove the rest of the deleted files by opening the recycling bin and selecting everything that is unnecessary. 

Delete Hidden Files

Your computer or laptop allows you to hide certain files to protect them from someone who is not supposed to access them.

When you hide your files, they still take up a certain amount of SSD space, even if you can’t see them. At some point, they may become useless to you, but you forget about them since you can’t see them.

If you see that your SSD is full and can’t figure out why this is happening, the hidden files may be the culprit. In this case, you should delete the hidden files to create some more space in your SSD. To show and delete the hidden files:

  1. Go to the Control Panel using the search bar.
  2. Find File Explorer Options.
  3. A new window will appear; go to View.
  4. Check the box next to Show hidden files, folders, and devices.
  5. Your hidden files will appear; delete any unnecessary ones.

If you have a Mac, finding and deleting hidden folders may be a more complex process, but there are multiple ways to make sure you find and delete your hidden files.

Uninstall Programs

You may need to install new apps or programs that become useless when working on different projects.

You may forget about them while your device is working as usual, but once it slows down, you need to delete them. To delete unnecessary programs or apps from your Windows device, follow these steps:

  1. Go to the search bar and type Apps and features.
  2. A new window will open; look for any apps that you find unnecessary.
  3. Click the Uninstall button to delete the app that you don’t need. 

To delete a program from your Mac, do the following:

  1. Open the Launchpad from the dock on the lower part of your screen, or pinch it closed with four fingers on the pad.
  2. Check the apps in the Launchpad; if you can’t find a particular one you want to delete, you can search for it by typing in the search bar in the upper part of your screen.
  3. Once you find the one, you want to delete, press and hold the Option until the apps start to shake.
  4. Tap the cross button on the corner of the app you want to delete.
  5. Select Delete to confirm.

Replace Your SSD

Installing an M.2 SSD into a laptop.

If you use all the above methods and your SSD is still slow, you may need to delete even more files. If there is nothing left to remove, you may need to replace your SSD with a higher-capacity one.

Thankfully, upgrading your SSD on your computer or laptop, even by yourself, is possible if you know exactly what to do.

This process may be a bit more complicated for Macs since the newer versions do not allow you to replace this part. However, you may be able to do the replacement in older models.

How To Avoid SSDs Slowing Down

Ideally, you should not fill your SSD in the first place. Once your SSD slows down considerably, it may not be able to return to its previous speed and performance, and you may need to replace it, as I explained above.

Luckily, you can avoid this issue now that you know all the problems that come with a full SSD. To ensure your SSD is never full beyond its capability, you should check its capacity often, using the instructions I have included above. 

Additionally, you should pay attention to the files and programs that are taking up SSD space. If you’re done with a large file that you won’t use again, you should delete it from your bin. Empty your recycling bin once in a while, making sure you keep any files that might be useful in the future.

Whenever you download a program for a specific purpose, remember to delete it once you’re done with it. There’s no point in keeping a program that will only occupy SSD space and do nothing.

How Much Free Space Should I Leave on My SSD?

As mentioned above, a helpful way of ensuring your SSD never gets full is to check the space left on your SSD once in a while. However, looking at the free space won’t make sense unless you know what percentage of free space is too low.

Generally, you should leave 30 percent of free space in your SSD. With only 70 percent of your storage device full, you can carry on with your tasks with no problem, and your computer won’t show any signs of issues.

However, the 30 percent estimation has been a rule for many years, dating back to when SSDs had smaller capacities and lower speeds. Nowadays, manufacturers are including new technologies and ideas that make your SSDs stronger and increasingly capable of handling these issues.

For instance, many manufacturers use overprovisioning to make sure that a percentage of your SSD is unavailable to you so that you can never fill the drive.

Even when you use all the available space, your SSD will not be full because there is some space left that you can’t access. Typically the amount of space unavailable to you is around 7 to 10 percent. 

Even with overprovisioning, your SSD can slow down and eventually become a problem for you. Overprovisioning is an extra measure to keep your performance as fast as possible, but it can’t make much of a difference on its own. To ensure your SSD performs well, you can leave around 20 percent of it empty.  

Final Thoughts

Solid-state drives are great devices that store information on your computer. They can be quite fast, but sometimes they slow down when full; this happens because the SSD needs more time to store data in partially empty blocks. 

A slow SSD can become a problem because it can cause the computer to boot more slowly and need more time to respond to your commands.

To avoid this situation, you should check your SSD capacity to ensure it doesn’t go beyond 80 percent. You can also try deleting files that might be taking up space.