What motherboard? What M.2 drive?
That depends on what you mean by performance and if you already have an SSD in your system. If you already have a SATA SSD it would make little to no difference unless you do a lot of large file transfers. If you are using a hard drive I would suggest a cheaper SATA SSD, it will improve boot times if widows is on the drive as well as make any programs on the SSD launch much faster, it will make the system feel overall more responsive. However it wont improve framerate in games if that's what your looking for.
If you have a motherboard with no M.2 slot and it is older, you may be able to use a pcie adapter however you would likely be limited to only PCIE 2.0 speeds and 2 lanes. Which would limit the...