|Seagate Barracuda XT 3TB Hard Drive ST33000651AS|
|Reviews - Featured Reviews: Storage|
|Written by Olin Coles|
|Monday, 28 March 2011|
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Seagate Barracuda XT: SATA 3G vs 6G
This section illustrates how the Seagate Barracuda XT-series hard disk drive performs on various SATA interfaces, and what difference exists between them. When Benchmark Reviews first discussed the upcoming SATA 6Gb/s hard drive in our Seagate Barracuda XT Preview, I can honestly say that my expectations were optimistic. After all, it seemed that a 64MB cache buffer could really improve performance of this 7200 RPM disk, and designing it to be compliant with the third generation SATA specification was only going to raise the headroom for potential bandwidth speed. Being optimistic is very different from being convinced, and speculation doesn't offer the insight that benchmark performance tests can. In this section, Benchmark Reviews tests the Seagate Barracuda XT SATA 6Gb/s hard drive on three different platforms using the 2TB version of Seagate's Barracuda XT hard drive. Performance characteristics are comparable to the 3TB version.
To help compare and contrast performance differences, we've used three different test systems. All three have Intel's ICH10 Southbridge in common, a chip with a long driver development history that allows 3.0 Gb/s bandwidth throughput. The ASUS P7P55D Premium uses the Marvell 88SE9123 controller and the Gigabyte GA-P55A-UD6 motherboards utilizes a Marvell 88SE9128 SATA 6Gb/s controller. With the processor and memory matched as closely as possible between platforms, our test results should be as accurate as possible. On the ASUS and Gigabyte P55 motherboards our test performance on the ICH10 chipset was identical, so that specific test (labeled Intel P55/ICH10) is manufacturer non-specific.
Observing 4KB IOPS performance over four different SATA controllers, the Seagate Barracuda XT offered very little difference between them all. The ST32000641AS SATA 6Gb/s hard drive did perform well enough compared to other HDD storage devices, but it didn't seem to matter whether it was connected to SATA 3GBps or SATA 6Gb/s.
Switching to bandwidth speed tests didn't reveal anything new, and the difference between SATA controllers was almost irrelevant. As far as the Seagate Barracuda XT is concerned, this is good news. However, to add a little interest (and introduce our Marvell SATA-6G SSD Performance vs Intel ICH10 side piece that spawned from our tests), Benchmark Reviews offers the performance results of the OCZ Agility OCZSSD2-1AGT120G Solid State Drive while connected to each SATA controller.
The OCZ Agility is a MLC Solid State Drive based on the Indilinx 'Barefoot' controller, and is one of the most affordable high-performance SSDs currently on the market. Testing 4KB IOPS performance across four difference chipsets showed just how far Intel has come with their driver optimizations, and how far Marvell still needs to go. In the chart above, the OCZ Agility SSD performs at approximately 7,200 IOPS read, and 16,000 write on either the P55 or X58 platform and using Intel's ICH10 SATA controller. Switching to either the Marvell 88SE9123 or 88SE9123 SATA 6G controllers changed the IOPS performance dramatically, and IOPS dropped to approximately 5500 read and 8600 write. This equals a 28% improvement in IOPS read performance with Intel's ICH10 over Marvell's 9128/9123 chips, and 95% increase in write operations per second.
Results in bandwidth speed tests for the Agility SSD were very similar to the IOPS benchmarks. The X58 and P55 platforms produced roughly 222 MBps reads and 165 MBps writes, all while connected to the Intel ICH10 Southbridge. In comparison, the Marvell SATA 6G controllers produced approximately 154 MBps read speed, and 106 MBps write. This results in a 42% advantage for the ICH10 SATA 3G controller over Marvell's 9123/9128 SATA 6G controller in read speed, and a 55% advantage in write-to performance. Why, you might ask? It's all in the driver.
You see, Intel's ICH9 and ICH10 chips utilize a driver architecture that creates a virtual RAM-disk buffer for cached transactions. The amount of RAM-disk created depends on the chip and available system memory (which we detail in our spin-off article), but the combined driver refinement and memory cache capability lead to very high performance. This is where Marvell needs to grow, and do more than a simple reverse engineering Intel's work in creating their own driver.
Drive Hardware Tested