The ATIV Book 9 has an SSD storage medium which is better than the HDD storage medium found on most similar spec notebook PCs that were released more than two years ago. 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 in fact the best storage medium across all portable PCs of this type and age.
The worst storage medium amongst similar types of notebook PC is HDD.