knowledge2121 :
also, which 120-128GB 2.5" SSD do you recommend ? since samsung doesn't have a 2.5" 860 EVO 128GB drive...are these other options ?
if your laptop is spec'd for SATA3, anything rated close to 500/500MBs will be fine. if it supports pcie m.2 then great get a pcie m.2 card.
some people prefer MLC over TLC, but I like to pick the ones that have better warranties. Some of the Intel ssd's offer 5 year warranty, or even one of those Chinese/Taiwanese brands would do.
there's a steep curve of diminishing return when it comes to desktop and "noticeable" difference, so you don't need to pay up big for the pcie m.2 products if you don't plan on doing much video editing or other I/o intensive job.
most of the consumer ssd are respectable in single read/write performance but they are not well-made for multiple or simultaneous read/writes. those are usually reserved for the more expensive "enterprise" grade ssd.
what I would do is:
get a reasonably price ssd with good warranty offering
install windows or your choice of o/s on the SSD disk
put any paging file or swap disk on another physical hard disk (this can be a hdd if you want)
this should provide you with the optimum setup for everyday desktop use. if your laptop does not let you install a second hdd then just use one is quite alright too.