Few things are more frustrating than using an SSD and having it run slowly. I mean, the whole point of an SSD is getting blazing-fast speeds, at least that is how they are marketed to us anyway. When it comes to an SSD that is writing slower than its rated speed, there are a few different reasons why this could be. From hardware, to software, or maybe even a few settings, there are many things you can do to fix your SSD. Here are some of the things to look for when your SSD speeds just aren't quite up to par.

Low storage space

As with all storage devices, there is a limit to how much of its space you can use comfortably. If your SSD is over 90% full, you may start noticing it slowing down a bit. At this point, you will want to see if there are any files you can delete to free up some space so that your SSD can perform as it should. This also means that you won't get to utilize the full space of your SSD. So, on your new 2TB SSD, you may only be able to use around 1.6TB before you start running into performance issues. Checking your storage speed on Mac and Windows is quite easy.

You're moving data from other (slower) drives

This "weakest link" factor is another one of the main reasons for reduced performance, but don't worry, because the good news is that nothing is wrong with your SSD in this case. If your new SSD has a write speed of 7,500MB/s but the drive you are copying files from only has a read speed of 500MB/s, you will only be able to copy files as quickly as the slowest drive allows. While this may be annoying, at least it means your SSD is fine, you'll just have to wait a bit longer for your files to transfer.

Your motherboard has an older PCIe version

This one is easy to overlook. For PCIe-based SSDs, you will want to make sure your motherboard's PCIe version is the same or higher than that of your SSD. If your SSD is PCIe 4.0 and boasts speeds of up to 7,500 MB/s and your motherboard is only PCIe 3.0, your SSD will only reach speeds of the PCIe 3.0 limitation which is 3,500 MB/s. Most PCIe devices are backward compatible, so a PCIe 5.0 SSD will work on a PCIe 3.0 motherboard, but you will only be able to reach the speeds of the PCIe 3.0 hardware.

You're moving very large files

While the size of the cache on your SSD doesn't directly affect the write speed, it can make things seem slower depending on the types of files you are writing. The cache is going to be faster than the SSD itself, so when you start transferring a lot of smaller files, the cache will fill up quicker than it can actually send the files to the SSD. As long as the files you are transferring are smaller than the cache capacity, these will transfer almost instantly, although if there are too many of them it will take longer.

AHCI is disabled

Depending on the type of SSD you are using, you may see significant performance gains when enabling AHCI. AHCI is a protocol used by SATA controllers to communicate with storage devices. AHCI also allows users to take advantage of other features such as Hot-Plugging, NCQ (Native Command Queuing), and even TRIM. The easiest way to enable AHCI is in your computer's BIOS. Simply enter the BIOS, look for SATA Mode in the settings, and make sure it is set to AHCI.

Your drive is not optimized

The TRIM command is going to let your operating system know exactly which blocks on your SSD are free to write to. It will also let the operating system know which blocks are no longer needed and could be deleted to free up more space to write. If you are using a Windows operating system, such as Windows 10 or 11, Windows should automatically enable TRIM. However, this isn't always the case, so it's good to check this if you are running into any issues.

Firmware

Sometimes all it may take is a simple firmware update to get the most from your SSD. Firmware upgrades are quite common with most PC hardware, and can be a good thing to check when things just aren't running quite right. The best place to check is the product page for your device directly on the manufacturer's website to see if there are any available updates.

Hardware

Depending on the type of SSD you choose, the culprit of slow SSD write speeds could be anything from the SATA cable to the port you are using on your motherboard. Switching SATA ports is generally quite easy and something most people should be able to do. All you should have to do is unplug the SATA cable from its port on your motherboard and switch it to a different port. It could also be worth swapping out SATA cables to see if this fixes the problem. Those using M.2 SSDs may want to check what M.2 port they are using and look at its specifications to make sure it can handle the speed of the SSD being used.

Make sure your hardware is running correctly

It is important to make sure you are getting the most out of your PC hardware. When it comes to SSDs and storage, there are quite a few reasons why it may not be working at its rated speed. Checking SSD speeds can be as easy as downloading a program like CrystalDiskMark and running a simple test. From there, you can check your speed and start to diagnose and troubleshoot the issue. Hopefully you feel equipped now to get to the bottom of things.