I'm currently buying parts for a self build. I want to go with the Samsung 950 512GB as my only storage but have been told two storages would be better. It was suggested to me that the primary memory can slow over time and therefore the Samsung Pro 256GB as a main storage with large files (such as games) on a second drive as being the better option. Can anyone tell me if slow down is someting to concern about? If so, I'll go with two storages.