Which SATA Hard Drive is Faster?

by on July 12, 2007

Q: Which is faster, 400GB 4200RPM SATA Dual Hard Drive or 200 GB 7200RPM SATA Dual Hard Drive?

A: There are a few factors that affect the speed of a hard drive; the size of the hard drive, how the drive is partitioned, the number of Rotations Per Minute (RPM), the seek time of the hard drive, and the data throughput of the device. Serial ATA (SATA) II drives are much faster than their predecessors with a data throughput of 3.0Gbit/s, compared to the 1.5Gbit/s speeds of the first generation SATA drives.

If the two SATA drives you describe are second generation drives, what ultimately determines their performance will be size, RPM, seek time, partitioning scheme, and the speed of the machine they are installed on. The 4200RPM drive is most likely going to have a longer seek time than the 7200RPM drive and therefore it will be noticeably slower. The slower RPM and seek time will become more noticeable on the 400GB drive due to the size of the drive. Creating multiple partitions on a drive that large will help to improve the overall performance of the drive. Finally, these drives will perform best on systems with native SATA support as opposed to systems with SATA add-on cards.

Additionally, when manufacturers refer to Dual Drives, they are simply pairing two drives of a smaller size together and spanning them to create one drive on the system. Even though your PC may only recognize them as one drive, there are actually two physical drives (2x 200GB) in the system. In some cases it may be more cost effective to purchase one larger drive than purchasing Dual Drives for your system.