SSDs are one of the most common digital storage devices found inside modern computers. Performing faster, offering greater robustness, and producing practically zero noise, it’s easy to see why SSDs are slowly taking over from their HDD counterparts for many applications.
While solid-state drives function very similarly to hard disk drives, at least from a user’s perspective, maintaining SSDs is very different. One of the most common questions we hear is, “Should you defrag an SSD?”
The answer is “NO!”
But, why is this, and what can you do to keep your SSD running smoothly instead?
What Is an SSD?
A solid-state drive (SSD) is a digital storage device commonly found in smartphones, computers, and other devices with significant storage demands. As the name suggests, SSDs don’t have any moving parts; they use NAND flash memory instead.
Millions of minuscule switches known as floating gate transistors are found inside SSDs. These transistors can trap the electron flow within them, enabling them to continuously maintain the same “On” or “Off” state, even when they don’t have a power source. All of the data you store on your SSD is split and assigned to different transistor groups called Cells using a special microprocessor. Unfortunately, these Cells have limited lifespans, and they will fail when they have gone through too many write cycles.
Hard Disk Drives & Defragmentation
Unlike SSDs, hard drives use magnetism to store your data. This is achieved by splitting spinning metal platters into tiny sections called “domains,” with each domain having its own magnetic field that can be read by the head of an oscillating mechanical arm. Magnetic fields that point in different directions can store an “On” or “Off” state.
A disk defrag can improve the performance of a hard drive by reorganizing the stored data so that related information is laid out in a continuous structure. This enables the storage device to read data with less movement of its mechanical parts.
The proprietary file system and software used by macOS largely solve the fragmentation problem, saving you from having to optimize your drives in modern machines.
Should You Defrag an SSD?
There isn’t a practical reason to defragment an SSD. In fact, there are two good reasons to avoid defragging your SSD altogether.
No Performance Gain
Hard drives have to find data using mechanical arms and spinning platters, but they can still move between files with an impressive seek time of 15ms. Unfortunately, this starts to add up when files are fragmented, and this is why defragmentation is a good way to maintain the speed of an HDD.
Solid-state drives have an inherent advantage over hard drives; they can move between files and fragments without mechanical movement. This means that they can achieve seek times of about 0.1ms, rendering the effects of defragmentation unnoticeable.
Lowering the Lifespan of Your SSD
As mentioned above, SSDs have a limited rewrite capacity. The process of defragmenting a drive involves rewriting files to new positions on the drive, effectively lowering the lifespan of your SSD without providing any benefits.
SSD Optimization with TRIM
Invalid data can quickly build up on an SSD. Solid-state drives can’t delete entire blocks of data when some of the data within a block is still valid, leaving behind invalid data and forcing the drive to go through the process of moving and deleting data when space is required.
To make matters worse, solid-state drives cannot write data over existing data, having to delete the existing data before performing the new write. These issues can make writing new data take more time, reducing the write performance of the SSD more and more as time goes by.
TRIM is a command that can be issued to an SSD, forcing it to go through the process of cleaning blocks to remove invalid data. This can improve the performance of your solid-state drive by taking care of this work while it would otherwise be idle rather than during a data write.
This feature is activated with SSDs by default in Windows 10 and 11, but you can choose to turn it off. However, it is worth noting that using TRIM can make it impossible to recover files that you have deleted from your PC.
Avoiding SSD Defragmentation
Thankfully, Windows won’t try to defragment an SSD unless you tell it to. This makes it nice and easy to avoid performing this operation on your drive, even if you also have hard drives inside your machine.
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