Running Apple Diagnostics fixes slow internal SSD (how on earth?!?)

[dushant]

This problem still exists. It happens so randomly that, no one is unable to point to which event actually causes the slowing down of read write speeds.

 

[nottooloud]

Solved mine 100% by replacing the Crucial drive with a 2TB Samsung 870 EVO. The Crucial is in an external enclosure now, doing other things.