WD  Caviar GreenPower 1TB SATA Hard Drive - 16MB WD10000CSRTL A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and performance. Calculates optimum seek speeds to lower power consumption, noise and vibration. Delivers lower power consumption by automatically unloading the heads during idle to reduce aerodynamic drag. Perpendicular Magnetic Recording (PMR), to achieve even greater areal density. The motor shaft is secured at both ends to reduce system-induced vibration and stabilize platters for accurate tracking