Single Drive and RAID 0 SATA NCQ Performance with Seagate's Barracuda 7200.7

Seagate was the first drive manufacturer to put serial ATA, or SATA, hard drives on the streets. In 2003, Seagate delivered its Barracuda ATA V in a SATA version for all those early adopters starving for new technology. That Barracuda was more like an average trout when it came to performance, though. However, it did offer the low noise-level that Seagate has a reputation for delivering. A lot has changed in the nearly two years since 2003, though. Now, the top drives from major manufacturers feature the SATA interface and twice the capacity. The competition in this space has really been heating up since early 2003. Western Digital released its Raptor line of SATA hard drives that features 10,000 RPM spindle speed and near-SCSI performance levels. And Maxtor recently released its new DiamondMax 10 family of drives, which boasts features such as a 16 megabyte buffer and dual-processor technology.

Not to be outdone, this year Seagate became the first company to introduce SATA drives featuring Native Command Queuing, or NCQ, a feature that is included in the next generation SATA specification. Command Queuing has long been a feature in SCSI technology, but it is just now making its way into the ATA storage world. Native Command Queuing is a technology designed to improve the performance of SATA hard drives by optimizing the execution order of read and write requests sent to them. A standard SATA drive without NCQ technology will execute commands as they are received, but a SATA NCQ drive's internal command queue will be reordered for optimal performance on the fly. To optimize performance, NCQ technology reorders the commands in such a way that reduces the amount of seek time the drive needs to access data. In other words, the NCQ reordering algorithms utilize such information as the physical location of the data on the disk. A common analogy for NCQ is the way an elevator works - it stops at near floors first rather than the order in which the buttons were pressed, thus reducing the total amount of time to meet all requests (drop everyone off at the floor they selected). Native Command Queuing has the most profound effect on performance in multi-tasking and applications with heavy asynchonous I/O loads. An added benefit of NCQ is that it will probably increase the lifespan of drives that use it since the amount mechanical movement for seeking is reduced.

Today, Seagate offers a wide selection of Barracuda SATA NCQ hard drives. The SATA Barracuda 7200.7 has been around for more than a year, and it offers capacities from 80 to 160 gigabytes and an eight megabyte cache. The company's newest model and succesor to the 7200.7 is the Barracuda 7200.8, and it features capacities ranging from 200 to 400 gigabytes and either an eight megabyte or sixteen megabyte cache. In order to get the word out about NCQ and Seagate's implementation of it, Seagate sent Bjorn3D two 160 GB Barracuda 7200.7 SATA NCQ drives. In an effort to see if NCQ could make a noticeable difference in performance, I ran some tests on different drive configurations using my Intel 915P Express testbed. As you will see on the next page, the results show that NCQ is more than just hype.

One important thing to note about NCQ technology is that it requires not only a drive that supports it but also host-side support, meaning the PC that the drive is connected to must have a controller capable of using NCQ. Today, only Intel's 915 and 925 platforms with the Intel 82801FR I/O controller hub (ICH6R) have this feature, but AMD fans will have it when motherboards based on NVIDIA's nForce4 hit the streets.

For more information on SATA NCQ, check out Seagate's spin on it and serialata.org.