Samsung 840 Pro-Series MZ-7PD256BW 256GB 2.5" (7mm thick) SATA III Internal SSD Single Unit Version. Sequential Read Speed: 540MB/s, Sequential Write Speed: 520MB/s, 4KB Random Read Speed: 10,000 IOPS, 4KB Random Write Speed: 90,000 IOPS, Trim Support, Raid Support, Samsung MDX Controller, 2x nm Multi-Level Cell (MLC) Toggle NAND 1.0.