1TB 9.5mm Scorpio Blue 2.5-inch notebook drive. The announcement was significant in that it's the first drive of this capacity to squeeze that many bits into an industry standard 9.5mm, 2.5" SATA form-factor. To do this, WD drove areal density per platter in their 2.5" platform to 500GB. The Scorpio Blue 1TB drive spins at only 5400RPM but its performance is actually surprising. Since areal density per platter has increased significantly, the drive actually bests some 7200RPM drives."
Link to Original Source