The Asus B5602FBA Laptop Supports Single and Dual Drive Configurations. (Two M.2 NGFF (2280) Solid State Drives) Note: The primary M.2 slot-1 (SSD1) supports Generation 4.0 x4 PCIe Drives and the secondary M.2 slot-2 (SSD2) supports Generation 3.0 x4 PCIe Drives. If installing a Generation 4.0 x4 PCIe Drive in slot-2 (SSD2), the drive will run at Generation 3.0 x4 speeds.