|Introduction and Specifications|
|Samsung has roughly a trillion or so different products in virtually every market of the computing world, but one area where the company can occasionally be overlooked is in consumer storage. Samsung SSDs are plentiful, though, most notably inside of Apple’s MacBooks, and unlike many SSDs out there, they’re built entirely with Samsung-made components, from the controller to the Flash NAND and DRAM cache. In fact, Samsung is one of the largest Flash memory suppliers in the world.
There may be an advantage in keeping all your hens in one house, so to speak, as this ostensibly gives Samsung the ability to adjust to any problems more quickly than if it had to, for example, harangue the controller manufacturer for a critical update.
In any case, the latest generation of Samsung SSDs is the 840 and 840 Pro Series, and we took the 250GB version of the 840 SSD for a spin. Not literally, of course, because these aren’t HDDs. (Nerd joke.)
Although the 840 is packaged in the familiar 2.5-inch form factor, Samsung opted for the slimmest of chassis which measures just 7mm in height. We were also a little taken aback at how light the drive was; it’s just 53.5 grams and feels like it might float away if you don’t hang onto it. The black (or is it a deep gray?) chassis is all metal with a slick-looking silver band around the edge.
The 250GB 840 has a SATA 6Gbps interface and is rated for sustained sequential read/write speeds of up to 540 MB/s and 250MB/s with up to 95,000/62,000 read/write IOPS. There’s 512MB of Samsung LPDDR2 SDRAM cache on board, as well as a 3-core Samsung MDX controller and Samsung Toggle DDR 2.0 NAND flash memory.
Looking at the PCB, you can see that it’s neat and tidy. There are 8 NAND modules on board, and all of them are on the top side and pasted in a tight, clean grouping. There’s really nothing at all on the underside of the PCB.
Samsung included wear-leveling and auto garbage collection in the 840 Series, as well as AES 256-bit encryption, TRIM support, S.M.A.R.T. support, and WWN support. The 840 SSD also comes with some free software in the form of Samsung SmartMigration and Samsung Magician.
Samsung Magician is surprisingly feature-packed and includes handy system information and links to sites with user guides and manuals, in addition to a firmware updater; performance optimization tools; OS optimization tools; and secure erase, over-provisioning, and disk clone features.
In addition to the software, the 840 comes with the boilerplate documentation as well as a 3.5-inch mounting bracket with screws and a USB-to-SATA/SATA power adapter so you can connect the SSD externally to pretty much any computer with a USB port.
|Test Setup and SiSoft SANDRA 2012|
|Our Test Methodologies: Under each test condition, the Solid State Drives tested here were installed as secondary volumes in our testbed, with a standard spinning hard disk for the OS and benchmark installations. Out testbed's motherboard was updated with the latest BIOS available as of press time and AHCI (or RAID) mode was enabled. The SSDs were secure erased and left blank without partitions wherever possible, unless a test required them to be partitioned and formatted, as was the case with our ATTO, PCMark 7, and CrystalDiskMark benchmark tests. Windows firewall, automatic updates and screen savers were all disabled before testing. In all test runs, we rebooted the system, ensured all temp and prefetch data was purged, and waited several minutes for drive activity to settle and for the system to reach an idle state before invoking a test.
First, we ran SiSoft SANDRA, the the System ANalyzer, Diagnostic and Reporting Assistant. Here, we used the Physical Disk test suite and provided the results from our comparison SSDs. The benchmarks were run without formatting and read and write performance metrics are detailed below.
The SANDRA Physical Disk test plays well to the Samsung 840’s read throughput, as it posted the strongest score of the bunch. However, you can see that its overall performance is hampered by a weak write score, which is actually the lowest score in the whole field.
|ATTO Disk Benchmark|
|ATTO is another "quick and dirty" type of disk benchmark that measures transfer speeds across a specific volume length. It measures raw transfer rates for both reads and writes and graphs them out in an easily interpreted chart. We chose .5kb through 8192kb transfer sizes and a queue depth of 6 over a total max volume length of 256MB. ATTO's workloads are sequential in nature and measure raw bandwidth, rather than I/O response time, access latency, etc. This test was performed on blank, formatted drives with default NTFS partitions in Windows 7 x64.
Following what we saw in the SANDRA test, this SSD’s read score is far better than its write score in ATTO, both relative to itself and to the entire test bank. While the Samsung 840 posted nice numbers in the write test with the smallest transfer sizes--second only to the OCZ Vertex 4--it planed out hard right at the 4KB transfer size mark and stayed there, where it ended up with the lowest score most of the rest of the way out.
On the other hand with respect to read performance, the Samsung 840 cleaned up, starting out incredibly strong and maintaining the top throughput for the entire read test.
|HD Tune Benchmarks|
|EFD Software's HD Tune is described on the company's web site as such: "HD Tune is a hard disk utility with many functions. It can be used to measure the drive's performance, scan for errors, check the health status (S.M.A.R.T.), securely erase all data and much more." The latest version of the benchmark added temperature statistics and improved support for SSDs, among a few other updates and fixes.
The Samsung 840 SSD performed solidly in HD Tune for the most part. In the average transfer rate test, it scored within 30-40Mbps of the leaders while once again posting the weakest write score. Access time is apparently a strength of the Samsung 840, as it delivered the best write score of the group (although its read score wasn't as impressive here).
The 840 looked good in terms of CPU usage, delivering write performance that nearly matched the best score in the field and read performance that was right in the middle of the pack. Where this SSD performed best was in the burst rate test, which finally showed some parity in the drive's read and write scores; even better, the 840 was solidly in the lead pack compared to our other test drives.
|CrystalDiskMark is a synthetic benchmark that tests both sequential and random small and mid-sized file transfers using incompressible data. It provides a quick look at best and worst case scenarios with regard to SSD performance, best case being larger sequential transfers and worse case being small, random transfers.
Overall, the Samsung 840 did very well in our CrystalDiskMark tests. Again we see, in the sequential and 512K transfer tests, that this drive posts strong read scores and less impressive write scores; in both, it scored at the top in the former and at the bottom in the latter. In the 4K QD32 test, however, that write score came up significantly.
While the 840's read score in the 4K transfer test was solid, it was actually the write score that topped the charts for a change.
|AS-SSD Compression Test|
|Next up we ran the Compression Benchmark built-into AS SSD, an SSD specific benchmark being developed by Alex Intelligent Software. This test is interesting because it uses a mix of compressible and incompressible data and outputs both Read and Write throughput of the drive. We only graphed a small fraction of the data (1% compressible, 50% compressible, and 100% compressible), but the trend is representative of the benchmark’s complete results.
The Samsung 840 hung with the pack quite well in the AS-SSD read test, but it lagged significantly behind the field in the write test. It was, however, solidly consistent with its write scores at least, which is a good sign.
|PCMark 7 Storage Benchmarks|
|We really like PCMark 7's Secondary Storage benchmark module for its pseudo real-world application measurement approach to testing. PCMark 7 offers a trace-based measurement of system response times under various scripted workloads of traditional client / desktop system operation. From simple application start-up performance, to data streaming from a drive in a game engine, and video editing with Windows Movie Maker, we feel more comfortable that these tests reasonably illustrate the performance profile of SSDs in an end-user / consumer PC usage model, more so than a purely synthetic transfer test.
The PCMark 7 scores are for the most part completely uninteresting, which speaks well of all of the drives we’ve tested. The scores are clustered very tightly across the board, although it’s worth mentioning that the Samsung 840 is often at or near the top score in most of these tests.
|Summary and Conclusion|
|Performance Summary: The 250GB Samsung 840 Series SSD offers somewhat unbalanced performance; on the one hand, it bested our bank of SSDs in many of our read tests, but on the other hand, it came in dead last in too many write tests. For most traditional consumer/client applications, read performance is the most critical watermark. However, those looking for strong write throughput, as with video editing for example, might want to keep this in mind.
Samsung 840 Series SSD (250GB)
The 840 series comes in a slim chassis with a very tidy PCB, and Samsung’s included Magician software is an excellent value add. The mounting kit and SATA-to-USB adapter are nice touches to the whole package, too. There are certainly SSDs available that offer better consistency in terms of performance, not to mention a healthier balance between read and write speeds, but the Samsung 840 Series SSD does offer solid value. At a price of $189.99 and and a formatted capacity of 232.88GB, this SSD costs about $0.82 per gigabyte. That’s not necessarily the absolute best value we’ve seen thus far, but it’s close.
Depending on your storage requirements, a 250GB Samsung 840 SSD could be the only drive you need, and if you’re looking to save some cash on a build or when upgrading a notebook, slapping in one of these babies could be a great way to do so. You’d get overall strong performance and obviate the need for a second storage drive, all for well under two hundred bucks.
Like its predecessor, the Samsung 830 Series, the 840 had high-performing read and lower-performing write speeds, which tells us that this is an area Samsung needs to work on. The Samsung MDX controller inside these drives has promise, but the third-party controllers other SSD OEMs are using might be a more robust alternative right now.
If you’re looking around the high end of the market for an SSD, keep moving. However, the 250GB Samsung 840 is a pretty good drive that offers a great value for your dollar if you're interested in something a bit more cost-effective.