Samsung Spinpoint M 640GB HDD, 640 GB, 5400 RPM, 8 MB, 2.5", Serial ATA II Samsung Spinpoint M 640GB HDD. HDD capacity: 640 GB, HDD speed: 5400 RPM, Storage drive buffer size: 8 MB, HDD size: 2.5", Interface: Serial ATA II https://www.tomshardware.com/uk/reviews/notebook-hard-drive-750gb-640gb,2637.html Remember when 500GB was the most you could get from a notebook drive? It seems like most vendors have made the transition to 640GB. Western Digital even has its own 750GB model that fits within the 9.5 mm z-height. So, which of these drives is the best...