SATA Hard Drive Performance Tutorial

Drive Capacity, Buffer Memory, and Speed Issues Affect Performance

Jul 29, 2008

All SATA Hard Drives have a long list of performance specifications but many people buy based on price and capacity alone. This article discusses other important factors.

At one point in time SCSI hard drives were the gold standard when it came to high performance computer components. Today Serial ATA (SATA) drives far surpass comparable SCSI drives, and are the most common type of hard drive being sold commercially today. Like most computer accessories SATA hard drives come in many different models with varying capacities, platter speeds, and buffer memory sizes. This article will seek to explain the various specifications and help buyers make more informed decisions when comparing options.

SATA Hard Drive Capacity And Its Relationship To Drive Speed (RPM)

Larger hard drives are always better, right? Not if the primary purpose of the drive it to move data as fast as possible. Most SATA hard drives for desktop computers have 3.5" platters. The more platters that are sandwiched into the drive the higher the capacity. The problem is that larger platters cannot spin as fast as smaller platters without breaking, leaving most desktop hard drives sitting at a typical 7200 RPM drive speed. Some high end drives reach 10,000RPM speeds, but with the increased speed comes often greatly increased prices (and smaller capacity due to smaller platter diameters).

The Seagate VelociRaptor line of high performance, 10K RPM drives are examples of this phenomenon. A 300GB Velociraptor SATA drive currently sells for as much as five times more than a 7200 RPM drive of the same size. For consumers that are interested in this very confusing aspect of SATA hard drive design consider checking out this excellent article on hard drive performance by Patrick Schmid at Tom's Hardware.

Transfer Speed and SATA Hard Drive Performance

There are several types of SATA interfaces but currently SATA/300 is the most common in commercial products. SATA/300 drives offer peak transfer rates of up to 300 megabytes per second. In terms of performance the faster a hard drive can move the data to the motherboard, the faster the overall machine will be able to process data. For programs that require heavy hard drive usage such as fast action, graphics intensive games, this high maximum threshold is important, and the faster the drive can push the data the better.

SATA Hard Drive Buffer Size

At the same time, the size of the buffer memory on a hard drive can also play a minor role in the final rating of a particular drive. Buffer memory is a small amount (currently either 8 or 16 megabytes) of RAM that is physically located on the hard drive. It caches the most frequently used data from the drive, allowing that data to be pulled from the buffer. This in turn allows the drive to serve the data to the computer faster and with less wear on the drive's physical components reducing wear and possibly slowing hard drive failures over the long term. While buffer size does not seem to have an incredibly significant effect on overall SATA drive performance, it never hurts to have more.

In general, all but the most hard core gamers and video enthusiasts will be able to get by with economically priced, high capacity hard drives. For those that desire the top in performance and are willing to pay for it, the tips shown above will help guide any potential purchase.

The copyright of the article SATA Hard Drive Performance Tutorial in Computer Drives/Storage is owned by Chad Criswell. Permission to republish SATA Hard Drive Performance Tutorial in print or online must be granted by the author in writing.