It's not just scratch. It's also spare capacity and stuff to deal with level wearing. They also advertise the actual usable space as opposed to the 'max' space.

It's not just scratch. It's also spare capacity and stuff to deal with level wearing. They also advertise the actual usable space as opposed to the 'max' space. A SSD might actually have 256GB of space, but it'll be advertised as 240GB. They're actually fairly honest. Remember, most of the major SSD manufacturers -aren't- harddrive manufacturers. They're chip and memory manufacturers (which makes sense).