The Lenovo Y50 has an SSD storage medium which is better than most many processor core laptops that have been available for more than two years. Most similar spec portable PCs that were released more than two years ago have an HDD storage medium. Solid State Drives (SSD) store data in semiconductors on a circuit board rather than using magnetic or optical media. Solid State Drives have no moving parts which makes them very fast and reliable.
An SSD storage medium is actually the best storage medium across all laptops that have been around for a comparable time to the Y50.
An HDD storage medium is the worst storage medium amongst similar types of portable PC.