Manufacturer: Seagate Technology LLC
Product Name: Momentus XT Solid State Hybrid Drive
Model Number: ST750LX003
Price As Tested: $245 MSRP
Mechanical hard disk technology has been the traditional standard for decades, refined to the point where it can deliver massive storage capacity beyond 3TB. Recently introduced solid-state drive storage solutions have begun pecking away at the market share thanks to their tremendous speeds and operational performance. Each offers an advantage over the other, leading manufacturers to seek out a hybrid solution that delivers quick access and large data capacity. The original 500GB Seagate's Momentus XT hybrid had the right ingredients, just not enough polish. More than a year later, the Seagate Momentus XT 750GB solid state hybrid drive (SSHD) returns with a double-size 8GB SLC NAND flash SSD buffer fused onto a larger 7200-RPM hard drive. Seagate FAST Factor firmware and Adaptive Memory Technology negate the need for third-party software, and makes this an all-in-one hybrid SSD solution. In this article Benchmark Reviews tests the Seagate Momentus XT (750GB model ST750LX003) in single and RAID-0 configurations against its predecessor, and several of the fastest notebook storage devices available.
The Hard Disk Drive (HDD) technology has enjoyed a long service life in the computer industry, and only recently have Solid State Drive (SSD) storage solutions threatened to replace it. While the HDD offers higher capacity at a better price per Gigabyte, SSDs offer tremendous speeds and operational performance. Seagate believes they've achieved the optimal blend of each, presenting their second-generation solid state hybrid drive. Seagate's Momentus XT 750GB Hybrid relies on an Adaptive Memory technology works by identifying patterns in how often certain digital data is used, which caches qualified user data access transactions onto the 8GB SSD. We experiment with two Seagate Momentus XT Hybrid drives in a striped RAID-0 array to see just how well Adaptive Memory Technology keeps up. Yet, while the name is Solid State Hybrid Drive (SSHD), the product is really a 'smart' HDD with extremely large memory buffer.
When SSD storage devices first arrived to market, hardware review websites had to gradually understand the new technology and how to benchmark its performance. Testing SSDs required more preparation than HDD benchmarks, and operational performance was vastly more relevant then traditional transfer speeds. For this purpose, our usual collection of benchmark test-metrics won't paint an accurate picture. ATTO and Iometer will offer traditional measurements, but these performance readings will ignore Seagate's Adaptive Memory algorithm that improves the operation of accessing these programs and not the benchmark results. Repetitive processes will benefit from SSD-like performance, but one-time file transfers and initial application access will be handled by the enhanced hard drive. In addition to traditional HDD/SSD benchmark tests, the Seagate Momentus XT Solid State Hybrid will be used for real-world tasks and compared against the competition.
Bandwidth Speed vs Operational Performance As we've explained in our
SSD Benchmark Tests: SATA IDE vs AHCI Mode guide, Solid State Drive performance revolves around two dynamics: bandwidth speed (MB/s) and operational performance (IOPS). These two metrics work together, but one is more important than the other. Consider this analogy: operational IOPS performance determines how much cargo a ship can transport in one voyage, and the bandwidth speed is how fast the ship moves. By understanding this and applying it to SSD storage, there is a clear importance set on each variable depending on the task at hand.
For casual users, especially those with laptop or desktop computers that have been upgraded to use an SSD, the naturally quick response time is enough to automatically improve the user experience. Bandwidth speed is important, but only to the extent that operational performance meets the minimum needs of the system. If an SSD has a very high bandwidth speed but a low operational performance, it will take longer to load applications and boot the computer into Windows than if the SSD offered a higher IOPS performance.
Closer Look: Seagate Momentus XT The Seagate Momentus XT Solid State Hybrid Drive looks identical to other 2.5" notebook hard drive storage products, so there's not much to report on the appearance. However, it's the inside of this drive that makes it unique. An 8GB Single-Layer Cell (SLC) NAND flash memory resides near two disk platters, and makes up the drives SSD cache. These platters have an operating rotational speed of 7200 RPM on the 750GB Seagate Momentus XT, and paired to 32MB of DRAM buffer memory. Going forward, Seagate has retired the 250GB and 320 capacities for Momentus XT, but continues to offer the 500GB first-generation version along with the new 750GB second-generation product:
• 500GB Momentus XT - ST95005620AS (first generation)
• 750GB Momentus XT - ST750LX003 (second generation)
Seagate's Momentus XT is best suited for notebook computer installations that fit a 2.5" drive, but this Solid State Hybrid Drive can easily be installed into most desktop systems without the need for any adapter. Seagate Momentus-XT hybrid drives have been designed with a focus on enhancing real-world user experience while maintaining a large storage capacity. Using their refined Seagate Adaptive Memory Technology, the Seagate Momentus XT learns which programs need to be cached onto the SSD all based on actual usage patterns.
While marketed as a Solid State Hybrid Drive, the Seagate Momentus XT is actually a hard drive first and foremost. This means that if the 8GB SSD cache ever fails, which is unlikely given that its uses single-layer cell (SLC) NAND flash components, the Momentus XT continues to operate as a hard disk drive without any lost data. This could prove critical for those users in need of a less volatile storage solution.
While Momentus XT is more like a hard drive than a SSD, it's still very different than your average hard drive. For example, the WD VelociRaptor features and operating shock (read) value of 65G measured at 2-ms, and non-operating shock of 300G. Conversely, all Momentus XT SSHDs are safe up to 350G's operating shock and 1000G's non-operating.
In the next few sections we test how well the new 2nd-generation 750GB Seagate Momentus XT compares to the 1st-generation 500GB model, as well as other hybrid and solid-state storage solutions. Join us...
SSD Hybrid Features At the core, Momentus XT is a high-performance 7200RPM drive with 32MB of drive level caching and a SATA 6Gb/s interface. Integrated into the electronics of the drive is 8GB of Single Level Cell (SLC) high- speed NAND flash. Momentus XT features a new technology - Seagate FAST Factor - to synergize the communication and data intelligence between the NAND and rotating media. FAST Factor and Adaptive Memory Technology combine to create a user experience of instant response, instant boot and instant gratification.
FAST Factor Technology According to Seagate, FAST Factor boot gives laptop users the instant response they need to get moving fast. Booting nearly as fast as an SSD, the Momentus XT drive with FAST Factor boots up to 3 times faster than a traditional 5400RPM drive in a laptop PC. Your boot-up time will never slow you down again. Bottom line: You get up and running faster.
FAST Factor flash management provides seamless integration of hardware, firmware and high-speed NAND flash while maintaining data under all configurations-in any system, using any operating system and with any driver. For fast application loads and overall SSD-like speed of response from your system, FAST Factor flash management keeps you moving. Bottom line: You get up and running faster with the applications you use most.
Seagate Adaptive Memory Technology Adaptive Memory technology is a self-learning algorithm designed to deliver SSD-like response from your favorite applications and files. Adaptive Memory selectively copies data that is the most frequently read and time-consuming to retrieve into the flash, giving you an instant-response experience.
Momentus XT Specifications
Drive Testing Methodology Solid State Drives have traveled a long winding course to finally get where they are today. Up to this point in technology, there have been several key differences separating Solid State Drives from magnetic rotational Hard Disk Drives. While the DRAM-based buffer size on desktop HDDs has recently reached 64 MB and is ever-increasing, there is still a hefty delay in the initial response time. This is one key area in which flash-based Solid State Drives continually dominates because they lack moving parts to "get up to speed".
However the benefits inherent to SSDs have traditionally fallen off once the throughput begins, even though data reads or writes are executed at a high constant rate whereas the HDD tapers off in performance. This makes the average transaction speed of a SSD comparable to the data burst rate mentioned in HDD tests, albeit usually lower than the HDD's speed.
Comparing a Solid State Disk to a standard Hard Disk Drive is always relative; even if you're comparing the fastest rotational spindle speeds. One is going to be many times faster in response (SSDs), while the other is usually going to have higher throughput bandwidth (HDDs). Additionally, there are certain factors which can affect the results of a test which we do our best to avoid.
Test System • Motherboard: ASUS P8P67 EVO (Intel P67 Sandy Bridge Platform, B3 Stepping)
• Processor: Intel Core i7-2600K 3.4 GHz Quad-Core CPU
• System Memory: 16GB Kingston DDR3 1600MHz CL6-6-6-18 ◦4GB RAM-Disk partition from system memory
• SATA 6Gb/s Storage HBA: Integrated Intel P67 Controller ◦AHCI mode - Intel Rapid Storage Technology Driver 10.1.0.1008
• SATA 3Gb/s Storage HBA: Integrated Intel P67 Controller ◦AHCI mode - Intel Rapid Storage Technology Driver 10.1.0.1008
• Operating System: Microsoft Windows 7 Ultimate Edition 64-Bit with Service Pack 1 ◦No page file allocated to virtual memory
Storage Hardware Tested The following storage hardware has been used in our benchmark performance testing, and may be included in portions of this article:
• OCZ RevoDrive Hybrid RVDHY-FH-1T MLC PCI SSD (Firmware 1.15)
• OCZ Vertex 3 VTX3-25SAT3-240G 240GB MLC SATA SSD (Firmware 1.15)
• Seagate Momentus XT 500GB SATA SSHD ST95005620AS
• Seagate Momentus XT 750GB SATA SSHD ST750LX003
• Western Digital Caviar Black 750GB 7200RPM SATA HDD
Benchmark Software • AS SSD Benchmark 1.6.4067.34354: Multi-purpose speed and operational performance test
• ATTO Disk Benchmark 2.46: Spot-tests static file size chunks for basic I/O bandwidth
• Futuremark PCMark 7: Primary Storage Suite tests real-world drive performance
Test Results Disclaimer This article utilizes benchmark software tools to produce operational IOPS performance and bandwidth speed results. Each test was conducted in a specific fashion, and repeated for all products. These test results are not comparable to any other benchmark application, neither on this website or another, regardless of similar IOPS or MB/s terminology in the scores. The test results in this project are only intended to be compared to the other test results conducted in identical fashion for this article.
Alex Schepeljanski of Alex Intelligent Software develops the free AS SSD Benchmark utility for testing storage devices. The AS SSD Benchmark tests sequential read and write speeds, input/output operational performance, and response times. Because this software receives frequent updates, Benchmark Reviews recommends that you compare results only within the same version family.
For the purpose of testing Solid State Hybrid Drive (SSHD) products, we've concentrated more on transfer speeds and less on 4K IOPS. After running several sequential read and write benchmarks to cache the test, the Seagate Momentus XT 750GB reported consistent results that appeared to rely on hard disk performance. After ten cache tests, the Seagate Momentus XT hybrid drive continued producing a 102.26 MB/s read and 97.71 MB/s write speed.
Seagate Momentus XT 750GB Solid State Hybrid Drive Combining two Seagate Momentus XT 750GB Solid State Hybrid Drives into a striped RAID-0 array yields much faster sequential speeds: 213.65 MB/s read and 216.77 MB/s write. These results are slight more than double the performance of a single Momentus XT SSHD, which will make our other tests much more interesting to compare.
RAID-0 Seagate Momentus XT 750GB Solid State Hybrid Drives The chart below is sorted by total combined sequential performance, which illustrates the differences in basic read/write speeds:
Benchmark Reviews tests transfer rates using ATTO Disk Benchmark. source:benchmark reviews
