This is a brand new WD 1TB drive that came with my NVR which I upgraded right away.

The Western Digital WD11PURZ 1TB Internal Surveillance Hard Drive Purple is a reliable and high-capacity hard drive designed for use with PCs. With a rotation speed of 5400 RPM and a storage capacity of 1TB, this SATA III drive offers fast read speeds of up to 500MB/s. The purple color indicates that this drive is specifically designed for surveillance systems, and it features low noise levels for quiet operation. It is a 3.5-inch form factor internal desktop drive, making it compatible with a variety of systems.