WD Purple drives are built for 24/7, always-on, high-definition security systems. WD Purple surveillance storage feature Western Digital’s exclusive AllFrame technology, so you can confidently create a security system tailored to the needs of your business. Using AllFrame technology, WD Purple drives improve video capturing and helps to reduce errors, pixelation, and video interruptions that could happen in a video recorder system. WD Purple drives have an enhanced workload rating that supports systems designed for 24×7 video recording with up to 64 cameras. Disk Speed (RPM) – 7200rpm.