What is SSD Over Provisioning

If you are in the market looking for a solid-state drive, the chances are that you might see the same solid-state drive have two different storage spaces mentioned on the box. As far as the larger number from the two is concerned, that is representing the total flash capacity of the drive, whereas the smaller number represents the actual space that you can use on the drive.

The simplest reason why you are seeing something like this on a solid-state drive is that that drive has been over-provisioned by the manufacturer.

So, What is SSD Over-Provisioning?

In the simplest terms, SSD over-provisioning happens when a certain free space in an SSD is allocated to make sure that the lifespan of SSD is increased as well as the overall performance and endurance. This is done by giving a permanent “Swap space” to the controller of the drive. The controller then uses that space to make sure that all the data traffic and storage for the drive is properly managed.

By doing so, every time the SSD has to read or write data, it no longer has to spend time preparing the space because that part is already being taken care of at the back end. Activities like Garbage Collection, Wear Leveling, as well as Bad Block Management, are handled through over-provisioning.

Are There Any Benefits of SSD Over-Provisioning?

So, now that we know what over-provisioning in terms of SSD is, are there any real-life benefits of something like this?

Well, there surely are. Right now, we are going to be looking at those benefits.

  • Improved Performance: First things first, through over-provisioning, the drive’s performance is improved. The main improvement comes in the form of an increase in random read/write performance as well as IOPS that are providing the flash controller with additional buffer space for handling program/erase cycles and also ensuring that the write operations have the access to the pre-erased block.
  • Sustainable Performance: Another benefit is that with over-provisioning, the drive stays as fast as it was even when the read/write cycles are being filled. This is done by making sure that the flash controller has the right space that it needs to perform its functions.
  • Better Endurance: With the help of over-provisioning, the total number of writes and deletes are evenly spread out throughout the area of the NAND flash blocks and pages. This ensures that the endurance of the drive remains consistent throughout.
  • Longer NAND Flash Life: With over-provisioning, your solid-state drive learns to work smarter, instead of working like a workhorse. This ensures that the wear and tear from constant read and write do not happen.
  • SSD Safeguard: The “swap space” is basically the safeguard that makes sure that the user does not go ahead and fill the drive. The extra space available ensures that the SSD has the ability to run tasks such as TRIM as well as Garbage Collection.
  • Reduced Power Consumption: Since over-provisioning makes the flash controller and the drive work in a smarter way, the overall power consumption gets reduced since there is not a lot of hard work being done.
  • More Reliable: The NAND flash fabrication processes have become a lot more complex, and they continue to do so. Manufacturers are now able to put more flash memories onto smaller chips than before. Over-provisioning is a feature that is becoming more and more common because it ensures increased reliability.
  • Improved Wear Leveling: Thanks to over provisioning, the controller can constantly move the data around in order to make sure that the cells that are in the flash have an even wear and tear. This helps in preparing the free blocks as well so they can be used in the future for data write, and reads. This also helps in extending the lifespan of the NAND cell.
  • Efficient Garbage Collection: Another benefit of over-provisioning is that with it, the Garbage Collection process does not take as long as it would otherwise. The background process gets handled sooner and in a much more efficient way.

How Much Space Will I Get?

Now that you know what the benefits of SSD over-provisioning are, the next step that we need to know is just how much space will you be getting. This is an important thing that most people seem to forget.

So, if you have just bought an SSD, and you are wondering how much space you are going to get, refer to the table below to have a proper understanding.

Total Space Actual Space
128GB 120GB
256GB 240GB
512GB 480GB
1TB 960G
2TB 1920GB

On the left, you have the advertised capacity, and on the right, you have the actual capacity that you will be able to use. If you do the math, the over-provisioning space is roughly 7 percent of the actual capacity, which is not bad by any means.


In conclusion, it is safe to say that SSD over-provisioning is most certainly a good thing. It is good that we talked about it because there is a common theory that the consumers are being ripped off by the manufactures.

As a matter of fact, if it weren’t for SSD provisioning, most of our drives would start failing a lot sooner than later.