The new drive is PCIe 4 -- which is actually faster than the system can support (it's a PCIe 3 interface). If the new drive is faster within the PCIe 3 realm, then moving the OS and everything else onto it may make sense -- if what you're looking for is PCIe 4 speeds (that is, the rated speed of this drive) -- the system cannot provide that.  
Was running out of storage space and I added Samsung 980PRO 1T SSD to my 7550. It looks like that Samsung SSD is faster than OEM SSD. Would you suggest to move everything from my 250G SSD that came with my 7550 to the new drive or just an OS. Thanks
Added Samsung 980Pro 1T SSD