Seagate Desktop HDD ST3400820AS - Hard drive - 400 GB - internal - 3.5" - SATA 3Gb/s - 7200 rpm - buffer: 8 MB

Key Features and Benefits:

• Maximize hard drive storage densities
  Seagate Desktop HDD, 1TB-per-disk technology incorporates 340,000 unique tracks in the width of a single inch. This incredible storage density drives new capacity possibilities and lowers your total storage costs.
• AcuTrac technology
  Seagate AcuTrac technology enables storage densities with accurate reading and writing to nano-sized tracks that are only 75 nanometers wide! That's about 1/500th the size of the period at the end of this sentence.