When Seagate told us it would be shipping the first 6Gb/s SATA hard drive, we were a little surprised. And when we found out it wasn’t going to be a solid state drive, but a 7,200rpm Barracuda drive, our skepticism increased. Sure, we’d been waiting a long time for Seagate’s 2TB 7,200rpm drive, and it’s nice to see the SATA 6Gb/s spec ship on a real-world product, but putting a 6Gb/s controller on a mechanical hard drive is like putting a Formula 1 airfoil on a golf cart. The vehicle just ain’t ever going to go fast enough to warrant the accessory.
In order to test the Barracuda XT on a level playing field, we built a new rig: a 2.66GHz Core i5-750 and 4GB of DDR3 RAM on an Asus P7P55D-Premium motherboard, which has an onboard Marvell SATA 6Gb/s controller as well as an Intel 3Gb/s SATA controller. The rig runs Windows XP SP3 and 64-bit Vista Home Premium from a 300GB WD Raptor. We tested both the Barracuda and its closest competitor, the 2TB WD Caviar Black, on both the Marvell and Intel controllers.
On the Marvell controller, the Barracuda reached average sustained read speeds of 108.3MB/s and average sustained writes of 102.3MB/s—only slightly faster than on the Intel controller. Random access times were within a few fractions of a millisecond on both controllers, averaging 14ms for random reads and 7ms for random writes, though reads were faster on the Intel controller and writes were faster on the Marvell. Strangely, burst transfer rates on the Marvell controller were nearly 30MB/s slower than on the Intel—186MB/s versus 214MB/s.
We saw the same pattern when we tested the WD Caviar Black 2TB on the Marvell and Intel controllers—random reads were faster on the Marvell, and random writes on the Intel, and burst speeds were significantly higher on the 3Gb/s controller. But this time the drive’s average sustained write speeds took a huge hit—from 112MB/s on the 3Gb/s Intel controller to 99MB/s on the 6Gb/s Marvell controller.
Though we give Seagate props for being the first hard drive manufacturer to include a 6Gb/s SATA interface, it’s of questionable utility—the technology just isn’t mature enough to warrant inclusion on a mechanical hard drive. The Barracuda XT’s performance on a 3Gb/s SATA controller rivals the Kick Ass 1TB Barracuda 7200.12, though it’s much more expensive. So don’t sweat it if you don’t have a board with 6Gb/s SATA yet (and who does?). However, the WD Caviar Black has higher average sustained transfer rates, lower random access times, and a higher burst transfer rate, so it remains our champion high-capacity drive.