Samantha prides herself on "never forgetting a face," although she frequently cannot put the correct name with a specific "face." this shows that samantha is

this shows that samantha is better at recognition than at recall

A memory that came from a recognition need a specific trigger in order to be accessed, so when samatha see a face, it trigger something in her memory that remind her the name of the person.
Recall on the other hand, require digging into memory without any trigger and samantha  is lacking on this area