But defragmenting could easily write hundreds of GB of data, which would wear out an SSD much faster. With typical users writing less than 20GB per day on average, it would require more than 20 years to burn through 150TB of writes. It's not something that would happen quickly-a 500GB Samsung 850 Evo as an example is rated for 150TB of total writes, or the equivalent of writing to every block of the drive at least 300 times. There are also extra blocks that aren't user-accessible that the algorithms can use to keep the drives from wearing out.īecause of the way SSDs work, not only does data not become fragmented but running a defragmentation utility will actually burn through the program/erase cycles and potentially cause premature 'death' of your SSDs. To avoid individual cells that contain frequently changed data from wearing out faster, SSDs track usage of each block, and the wear-leveling algorithms ensure that over time, the cells on an SSD are written a similar number of times. Each cell in a modern SSD can be written to about 3,000 times before the cell stops working properly.

The reason is that the NAND gates wear out over time, and are rated in program/erase cycles. SSDs don't just eliminate moving parts and improve access times, they also have built-in wear-leveling algorithms.

But there's more to the story than just speed.

Instead, SSDs access flash memory (NAND) at much higher speeds, typically less than 50us-that's 50 microseconds, or compared to a typical hard drive with a 15ms average access time, about 300 times faster. The reason there's no point defragmenting an SSD is that there's no seek time or rotational latency.

Windows defrag ssd