The Seagate Barracuda 250GB 3.5" ST250DM000 is an internal hard disk drive with a rotation speed of 7200 RPM, offering a storage capacity of 250GB. It features a cache size of 16MB, and a transfer rate of 600MB/s. With its reliable Seagate brand reputation and compact 3.5-inch form factor, this drive is good for running your operating system.This Seagate Barracuda has a Kingston SA400S37/240G, 2.5" SATA III Internal SSD, Model A400, mounted on it. That gives you a total of 490GB.