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SSD 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 32 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 Drives 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.
EDITOR'S NOTE 04-May-2010: Crucial Technologies has released the first public firmware update (version 0002) for the C300 SSD series, available here.
SSD Testing Disclaimer
Early on in our SSD coverage, Benchmark Reviews published an article which detailed Solid State Drive Benchmark Performance Testing. The research and discussion that went into producing that article changed the way we now test SSD products. Our previous perceptions of this technology were lost on one particular difference: the wear leveling algorithm that makes data a moving target. Without conclusive linear bandwidth testing or some other method of total-capacity testing, our previous performance results were rough estimates at best.
Our test results were obtained after each SSD had been prepared using DISKPART or Sanitary Erase tools. As a word of caution, applications such as these offer immediate but temporary restoration of original 'pristine' performance levels. In our tests, we discovered that the maximum performance results (charted) would decay as subsequent tests were performed. SSDs attached to TRIM enabled Operating Systems will benefit from continuously refreshed performance, whereas older O/S's will require a garbage collection (GC) tool to avoid 'dirty NAND' performance degradation.
It's critically important to understand that no software for the Microsoft Windows platform can accurately measure SSD performance in a comparable fashion. Synthetic benchmark tools such as HD Tach and PCMark are helpful indicators, but should not be considered the ultimate determining factor. That factor should be measured in actual user experience of real-world applications. Benchmark Reviews includes both bandwidth benchmarks and application speed tests to present a conclusive measurement of product performance.
Test System
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System Memory: 6GB Triple-Channel DDR3 1600MHz CL6-6-6-18
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SATA 3Gb/s Storage HBA: Integrated Intel ICH10R Controller
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SATA 6Gb/s Storage HBA: Integrated Marvell SE9128 Controller
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Operating System: Microsoft Windows 7 Ultimate Edition 64-Bit
Drive Hardware Tested
The following storage hardware has been used in our benchmark performance testing, and may be included in portions of this article:
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Hitachi Travelstar 5K160 2.5" 40GB SATA 5,400 RPM HDD HTS541640J9SA00 (8MB Cache Buffer)
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Hitachi Travelstar 7K100 2.5" 60GB SATA 7,200 RPM HDD HTS721060G9SA00 (8MB Cache Buffer)
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Intel X25-E Extreme SATA-II SLC SSD SSDSA2SH032G1GN
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Seagate Momentus 5400.6 320GB ST9320325AS 2.5" 5,400 RPM SATA-II Hard Disk Drive
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Western Digital VelociRaptor 300GB WD3000HLFS 10,000 RPM SATA Hard Disk Drive (16MB Cache Buffer)
Test Tools
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System Speed Test v4.78 by Vladimir Afanasiev: Accurately measures random access response time
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ATTO Disk Benchmark v2.34: Spot-tests static file size chunks for basic I/O bandwidth
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HD Tune Pro v3.5 by EFD Software: Measured random access IOPS and speed
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Iometer 2008.06.28 by Intel Corporation: Tests IOPS performance and I/O response time
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EVEREST Ultimate Edition v5.30.1900 by Lavalys: Disk Benchmark component tests linear read and write bandwidth speeds
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CrystalDiskMark v2.2 by Crystal Dew World: Sequential speed benchmark spot-tests various file size chunks
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HD Tach RW v3.0.4.0 by Simpli Software: Measures approximate buffered read and write bandwidth speeds
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