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Samsung SSD 840 EVO mSATA Review
Date: Mar 28, 2014
Author: Marco Chiappetta
Introduction and Specifications

A few months back, we took a look at Samsung’s SSD 840 EVO series of solid state drives. At the time, we found their performance to be quite good, and the drives were competitively priced too. Shortly after the 2.5” versions of Samsung’s SSD 840 EVO drives hit the scene, the company prepared an array of mSATA drives featuring the same controller and NAND flash. The Samsung SSD 840 EVO mSATA series of drives would be essentially identical to their 2.5” counterparts, save for the mSATA drives’ much smaller form factor.

We’ve got a 500GB Samsung SSD 840 EVO mSATA drive on tap for you here. Since the original release of the Samsung SSD 840 EVO series, the drives have received a couple of firmware updates that seem to have improved performance even further. You’ll see what we mean when you check out the benchmarks on the pages ahead, but before we get to the numbers here are some specifications and pics to get your juices flowing...


Samsung SSD 840 EVO mSATA
Specifications & Features

Usage Application  Client PCs* 
Capacity  120GB, 250GB, 500GB, 750GB and 1TB 
Dimensions (L* W* H)  30 x 50.8 x 3.8 (mm) 
Interface  SATA 6Gb/s (compatible with SATA 3Gb/s and SATA 1.5Gb/s) 
Form Factor  mSATA
Controller  Samsung MEX controller 
NAND Flash Memory  1x nm Samsung Toggle DDR 2.0 NAND Flash Memory (400Mbps) 
DRAM Cache Memory  256MB (120GB) or 512MB(250GB&500GB) or 1GB (750&1TB) LPDDR2 
Performance Sequential Read: Max. 540 MB/s 
Sequential Write: Max. 520 MB/s (250GB/500GB/750GB/1TB), 410 MB/s (120GB) 
4KB Random Read (QD1): Max. 10,000 IOPS
4KB Random Write(QD1): Max. 33,000 IOPS
4KB Random Read(QD32): Max. 98,000 IOPS (500GB/750GB/1TB), 97,000 IOPS (250GB), 94,000 IOPS (120GB)
4KB Random Write(QD32): Max. 90,000 IOPS (500GB/750GB/1TB), 66,000 IOPS (250GB), 35,000 IOPS (120GB)
TRIM Support  Yes (Requires OS Support) 
Garbage Collection  Yes 
S.M.A.R.T  Yes 
Encryption  AES 256-bit Full Disk Encryption (FDE)
PSID printed in SSD label 
Weight  Max. 53g (1TB) 
Reliability  MTBF: 1.5 million hours 
Power Consumption  Average :100mW*** (Typical) Idle : 45mW (Typical, DIPM ON) 
Temperature Operating: 0°C to 70°C
Non-Operating: -55°C to 95°C 
Humidity  5% to 95%, non-condensing 
Vibration  Operating: Random: 2.17Grms (7~800Hz) 
Non-Operating:  Random: 3.08Grms (7~800Hz) 
Shock  1500G & 0.5ms (Half sine) 
3 years limited
120GB at $99.99 and 500GB at $299.99 currently

Like their 2.5” counterparts, Samsung’s mSATA 840 EVO series of drives feature an updated, triple-core Samsung MEX controller, which operates at 400MHz. The controller is fundamentally similar to the triple-core MDX controller used in the original 840 series, though the MDX controller in those drivers operated at only 300MHz. The 840 EVO’s MEX controller has also been updated to support the SATA 3.1 spec, which incorporates a few new features, like support for queued TRIM commands, for example.

Along with the MEX controller, all of the Samsung 840 EVO mSATA series drives feature some LPDDR2-1066 DRAM cache memory. The 120GB drive sports 256MB of cache, the 250GB and 500GB drive have 512MB of cache, and the 750GB and 1TB drives have 1GB of cache. All of the current-gen Samsung 840 EVO mSATA drives are also outfitted with 19nm TLC NAND flash memory of varying capacities. The 250GB drive features two pieces of NAND (128GB, each), while the 500GB drive you see pictured here has 4 pieces (again, 128GB each). If you do the math, however, you’ll file that the drives leave roughly 9% of the NAND capacity for over-provisioning, which is typical of many current SSDs.


In addition to using a 19nm manufacturing process, Samsung has also dedicated a small portion of the TLC NAND used in these drivers to act like a SLC write buffer—Samsung calls the feature TurboWrite. This allows the TLC NAND to perform more like a MLC drive for writes, as long as the buffer isn’t exhausted. On a 250GB drive, TurboWrite buffer is about 3GB; on the 500GB drive we tested, the buffer is about 6GB.

TurboWrite In Action

TurboWrite should allow the 840 EVO series to perform very well in the vast majority of consumer-class workloads. As you can see in the screen-capture above (taken from HD Tune using a 1TB drive), writes are much faster when the TurboWrite buffer is being utilized, before they taper off.

Test Setup, IOMeter 1.1 RC

Our Test Methodologies: Under each test condition, the Solid State Drives tested here were installed as secondary volumes in our testbed, with a separate drive used 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 prior to testing, and left blank without partitions for some tests, while others required them to be partitioned and formatted, as is 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.

HotHardware Test System
Intel Core i7 and SSD Powered

Processor -

Motherboard -

Video Card -

Memory -

Audio -

Storage -


Hardware Used:
Intel Core i7-4770K

Gigabyte Z87X-UD7 TH
(Z87 Chipset, AHCI Enabled)

Intel HD 4600


Integrated on board

Corsair Force GT (OS Drive)
AData XPG SX900 (256GB)
SanDisk Extreme II (480GB)
Samsung SSD 840 EVO (250GB)
Samsung SSD 840 EVO mSATA (500GB)
OCZ Vertex 460 (240GB)

OS -
Chipset Drivers -
DirectX -

Video Drivers

Relevant Software:
Windows 8.1 Pro x64
Intel, iRST
DirectX 11

Intel HD

Benchmarks Used:
IOMeter 1.1.0 RC
HD Tune v5.50
ATTO v2.47
CrystalDiskMark v3.0.3 x64
PCMark 7
SiSoftware Sandra 2014

I/O Subsystem Measurement Tool

As we've noted in previous SSD articles, though IOMeter is clearly a well-respected industry standard drive benchmark, we're not completely comfortable with it for testing SSDs. The fact of the matter is, though our actual results with IOMeter appear to scale properly, it is debatable whether or not certain access patterns, as they are presented to and measured on an SSD, actually provide a valid example of real-world performance for the average end user. That said, we do think IOMeter is a reliable gauge for relative available throughput within a given storage solution. In addition there are certain higher-end workloads you can place on a drive with IOMeter, that you can't with most other storage benchmark tools available currently.

In the following tables, we're showing two sets of access patterns; our custom Workstation pattern, with an 8K transfer size, 80% reads (20% writes) and 80% random (20% sequential) access and a 4K access pattern with a 4K transfer size, comprised of 67% reads (34% writes) and 100% random access.

The Samsung SSD 840 EVO mSATA drive was right in the mix with some of the fastest drives we've tested with these IOMeter access patterns.

In terms of overall bandwidth, the Samsung SSD 840 EVO mSATA drive led the pack in our workstation access pattern, though it trailed a few other drives with the 100% random, 4K access pattern.

SANDRA and ATTO Disk Benchmark

Next we ran SiSoft SANDRA 2014, the the System ANalyzer, Diagnostic and Reporting Assistant. Here, we used the Physical Disk test suite and provide the results from our comparison SSDs. The benchmarks were run on unformatted drives and read and write performance metrics are detailed below.

SiSoft SANDRA 2014
Synthetic HDD Benchmarking


The Samsung SSD 840 EVO mSATA drive put up some excellent numbers in the lite-duty SANDRA file system benchmark, besting all of the other drives we've tested.

ATTO Disk Benchmark
More Information Here: http://bit.ly/btuV6w

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.

The Samsung SSD 840 EVO mSATA drive also rocked the ATTO disk benchmark. With transfer sizes in the 4K to 64K range, nothing else could touch it.

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.

HD Tune v5.50
More Info Here: http://www.hdtune.com

Access times fluctuated from best to worst with theSamsung SSD 840 EVO mSATA drive in the HD Tune benchmark, but bandwidth was once again among the best.

CrystalDiskMark Benchmarks

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.

CrystalDiskMark Benchmarks
Synthetic File Transfer Tests

More killer numbers from the Samsung SSD 840 EVO mSATA drive. It either left the pack or was among the fastest drives we've tested in this benchmark.

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.

AS-SSD Compression Benchmark
Bring Your Translator: http://bit.ly/aRx11n

The Samsung SSD 840 EVO mSATA drive's performance doesn't vary with the compressibility of data being transferred. And once again, it's performance is among some of the better drives we've tested.

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.

Futuremark's PCMark 7 Secondary Storage

All of the drives featured here performed within a couple of percentage points of one another in the trace-based PCMark 7 benchmarks. Though their margins of victory are relatively small, technically, the Samsung SSD 840 EVO mSATA drive (and its 2.5" counterpart) led the pack overall.

Samsung RAPID Mode

Another interesting feature of the Samsung SSD 840 EVO series is dubbed RAPID. RAPID is an acronym for Real-Time Accelerated Processing of I/O Data. It is a feature of Samsung’s Magician software (v4.2 or newer) that can speed up the drive significantly. The feature can be enabled with a single-click (followed by a reboot), in the Samsung Magician utility.

Samsung Magician Utility

Samsung acquired NVELO a while back, which was a company known for its SSD caching technology. NVELO’s software was used to accelerate hard drive transfers by buffering the most commonly accessed bits of data from the hard drive onto a faster SSD. Well, RAPID works in a similar manner, but in the case of the Samsung's 840 EVO series of drives, RAPID caches the most commonly accessed bits of data on the SSD into faster system memory.

ATTO Transfer Test with RAPID Mode Enabled

The size of the cache will dynamically adjust based on available system resources, and it follows the cache flush commands of the OS, so the risk of losing data due to an unexpected power outage isn’t much higher than a typical system using write buffering. The algorithms for RAPID are specifically tuned for solid state transfers, however, and are far more effective than any current-gen OS cache. The performance benefits of RAPID will vary depending on the age and frequency of the data being accessed, but when RAPID is being used, effective transfer speeds can hover in the 4GB's+ range. Yes, that's a G, as in gigabytes.

Our Summary and Conclusion
Performance Summary: The Samsung SSD 840 EVO series of mSATA solid state drives performed extremely well throughout our entire battery of tests. Whether using synthetic benchmarks, trace-based tests like PCMark, or highly-compressible or incompressible data, the 500GB Samsung SSD 840 EVO mSATA drive we tested offered class-leading performance. As evidenced by the ATTO Disk Benchmark, the 840 EVO excelled with small block transfers, where it outpaced a number of other drives by a significant margin.

The Samsung 840 EVO mSATA Solid State Drive

We liked Samsung’s 2.5” SSD 840 EVO series of solid state drives when we reviewed them a few months ago, and the mSATA versions are just as attractive, which is no surprise given their similarities. Performance is good and pricing is right in line with the competition. Street prices for the entire range of drives, in capacities of 120GB to 1TB are as follows:

As is typically the case, the cost per gigabyte of Samsung’s SSD 840 EVO series of mSATA drives decreases as capacities increase. So, the larger drive you can afford, the better the deal. And in light of many current competitive offerings, the 840 EVO series is downright affordable.

In terms of their performance, the Samsung SSD 840 EVO mSATA series of drives are clear winners. We can’t definitively speak to their long-term reliability since they’re relatively new, but based on past experience with Samsung’s drives, we don’t expect any surprises. Samsung is also offering a 3-year warranty on the drives, which is in-line with competing products. If you're in the market for a new solid state drive in the mSATA form factor, the Samsung SSD 840 EVO series should absolutely be one of your considerations, especially if you've got the budget for one of the larger capacity drives in the line-up.


  • Great Overall Performance
  • RAPID Mode Option
  • Competitively Priced
  • TLC NAND Technically Not As Durable as True MLC

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