WD Red 4TB NAS Internal Hard Drive - 5400 RPM Class, SATA 6Gb/s, SMR, 256MB Cache, 3.5" - WD40EFAX
"WD Purple™ drives are built for 24/7, always-on, high-definition security systems. With a supported workload rate1 of up to 180 TB/yr and support for up to 64 cameras, WD Purple™ drives are optimized for surveillance systems. WD Purple™ surveillance storage also comes with WD’s exclusive AllFrame 4K™ technology, so you can confidently create a security system tailored to the needs of your business. Using AllFrame 4K™ technology, WD Purple™ drives improve ATA streaming to help reduce errors, pixelation, and video interruptions that could happen in a video recorder system.
1Workload Rate is defined as the amount of user data transferred to or from the hard drive. Workload Rate is annualized (TB transferred ✕ (8760 / recorded power-on hours)). Workload Rate will vary depending on your hardware and software components and configurations."