Dell XPS 13 (9333, Late 2013) - Manual (Page 8)

Specifications
Views
System
Information
Memory
Ports and
Connectors
Dimensions and
Weight
Computer
Environment
Storage
Touchpad Power Adapter Camera
Communications
Battery
Video Audio
Display Keyboard
Memory
Type Dual‑channel DDR3L
Speed Up to 1600 MHz
Configurations supported 4 GB and 8 GB