Dell Alienware 15 (Early 2015) - Manual (Page 14)

Specifications
Views
System
Information
Memory
Ports and
Connectors
Dimensions and
Weight
Computer
Environment
Storage
Touch Pad Power Adapter Camera
Communications
Battery
Video Audio
Display
Media-Card
Reader
Keyboard
Storage
Interface SATA 6 Gbps
Drives supported One hard drive and two M.2 Solid State Drives (SSD)
Hard drive One 2.5‑inch drive
SSD Two M.2 drives