Seagate Constellation 250GB HDD, 250 GB, 7200 RPM, 64 MB, 2.5", Serial ATA Seagate Constellation 250GB HDD. HDD capacity: 250 GB, HDD speed: 7200 RPM, Storage drive buffer size: 64 MB, HDD size: 2.5", Interface: Serial ATA Currently, 2.5" enterprise drives are leaving their 3.5” competitors behind. They're faster, more flexible, and now they offer comparable capacities (we're up to 1 TB now). In this piece, it's Hitachi versus Seagate battling for high-density supremacy......