FSW is one of the three progs under Express Entry. FSW itself has a different scoring system (100 Points) where one needs to score over 67 points to be considered for the FSW prog. If one can cross this point threshold then his application goes into the EE pool and is then compared with others based on the CRS score. All EE applications are judged in the common pool using the CRS scoring system (600+ points).
If you have a job (Arranged employment) then you get 10 points in the FSW score and up to 200 in CRS (CRS – D. Additional points)