In fact, the reason for this difference is the company. Because of the variety of SSD hard drives available in the market. The read/write speed of each of these SSDs is the same. Usually, the read/write speed of an SSD is 500 Mb/S. However, the read/write of SSD which contains M.2 is much better than 3500 Mb/S. And these types of hard drives give you a lot more speed.
If you Use M.2 SSD Hard then You get much more speed. Check SSD speed on your computer.