The Western Digital Caviar WD400BB-75AUA1 internal hard drive is designed for space-hungry operating systems and applications. With an average seek time of 8.9 ms, this Western Digital 40 GB hard drive lets you find your files and folders seamlessly. Moreover, the 7200 RPM speed of the Western Digital Caviar WD400BB-75AUA1 proves advantageous in terms of access speed, especially when opening huge or multiple files. Thanks to the IntelliSeek feature, this Western Digital 40 GB hard drive calculates optimum seek speeds to minimize power consumption, noise, and vibration. Plus, the 3.5-inch form factor consumes less power, making this internal hard drive suitable for laptops, especially when running on battery power.