Seagate SSHDHD technology is up to 5 times faster than a standard 5400RPM notebook hard drive.

ENGADGET: Seagate ships its first desktop hybrid drive, third-gen laptop models

The 2 TB Western Digital drive has one more disks than can fit into a notebook 2.5-inch drive and that is why they are selling these for the external storage market.

FORBES: More Storage Means More Disks

Apple should consider extending the Fusion Drive concept to its higher end notebook computers in addition to the desktop computers.

FORBES: Will A Fusion Drive Approach Become Widespread in Computers?