The 320GB WD AV hard drive combines optimized AV performance with best-in-class power consumption and thermally optimized operation. With a MTBF of 1 million hours, this drive is designed to last in high temperature always-on streaming digital audio/video environments such as PVR/DVR, DVR recorders and surveillance video recorders.SilkStream technology enables smooth, continuous digital video playback of up to twelve simultaneous HD streams. IntelliSeek calculates optimum seek speeds to lower power consumption, noise, and vibration. With Preemptive Wear Leveling (PWL), the drive arm frequently sweeps across the disk to reduce uneven wear on the drive surface common to audio video streaming applications. WD AV drives have been tested for compatibility in a broad range of AV products including set top boxes, DVD recorders, and mainstream surveillance systems.