Samsung 840 EVO 128GB mSATA SSD Review

Following up the review of the impressive 1TB model, today Chris looks at the Samsung 840 EVO 128GB, the smallest EVO mSATA drive on the market.

Published Jan 8, 2014 9:00 AM CST   |   Updated Tue, Nov 3 2020 7:00 PM CST
Manufacturer: Samsung
10 minute read time


Samsung 840 EVO 128GB mSATA SSD Review 01

Following up to our review of the 1TB mSATA EVO, we have the smallest capacity size available from this new product group: the 120GB model. If you've followed SSDs for the last few years, you already know that smaller capacity drives write slower than larger models. For those that don't already know, let's cover why.

When the SSD controller reads and writes to flash, it does so through channels. You can think of the controllers channels to the flash as roads to a stadium (controller), from the suburbs (NAND flash). The more roads you have coming in, the faster people can get to the stadium and sit down. In SSD terms this is called parallelism; more data comes to the controller through more channels, since the bus width is fixed. Smaller SSDs have less NAND packages, so there are not as many roads to carry the data.

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The Samsung 840 EVO 120GB mSATA has just two NAND flash packages, with four-19nm die inside each package. Samsung rates the sequential performance at 540 MB/s read, and 410 MB/s write. Random IOPS performance listed for the 120GB capacity size is 94K read, and 35K write.

To achieve the high sequential write performance using TLC flash, Samsung uses an SLC like layer to cache writes. On the 1TB model, we observed a large SLC area due to the special area being on die, and the larger 1TB model has significantly more die than the 120GB model. What that means is that you have less of a cushion with the 120GB drive that we're looking at today. It's something we'll keep an eye on while during the testing phase of this review.

Looking at the spec sheet, we see Samsung's four new mSATA form factor drives that range in capacity from 120GB, to 1TB. The capacity sizes double at each higher capacity product SKU. The MSRPs are close to that of the EVO 2.5" models: 120GB ($149.99), 250GB ($259.99), 500GB ($489.99), and 1TB ($859.99). We suspect the MSRP prices will fall rapidly to get in line with the 2.5" models. The EVO mSATA models carry the same three-year warranty that the 2.5" models ship with in America.

Samsung 840 EVO 1TB mSATA SSD

Samsung 840 EVO 128GB mSATA SSD Review 01

We're just going to roll right through the product packaging images.

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Samsung 840 EVO 128GB mSATA SSD Review 03

The drive placement is in the middle of the packaging, so your 840 EVO mSATA is well protected during shipping.

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Inside the package, we found a warranty statement summary that doubles as a user manual, two Samsung SSD Activated stickers, and the drive.

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Here we get our first look at the drive. The label lists the part number, serial number, and capacity size.

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The backside has a few surface mount components, but no flash.

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The 120GB model has only two NAND packages, and they are on the main side with the controller and DRAM. There are four 128GB die in each package, so interleaving is limited on the 120GB model.

Benchmarks - Test System Setup and ATTO Baseline Performance

Desktop Test System

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Lenovo W530 - Mobile Workstation

We use two systems for SSD testing. The desktop runs the majority of the tests, and the Lenovo W530 runs the notebook power tests, as well as the real-world file transfer benchmark.

ATTO Baseline Performance

Version and / or Patch Used: 2.34

ATTO is used by many disk manufacturers to determine the read and write speeds that will be presented to customers.

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The Turbo Write feature on the flash partitions a small area on each die to SLC, and keeps the performance high for write bursts. ATTO doesn't pass enough data to see past the SLC layer in this sequential test. We achieved 554 MB/s sequential read, and 533 MB/s sequential writes.

Benchmarks - Sequential Performance

HD Tune Pro

Version and / or Patch Used: 4.00

Developer Homepage:

Product Homepage:

HD Tune is a Hard Disk utility which has the following functions:

Benchmark: Measures the performance

Info: Shows detailed information

Health: Checks the health status by using SMART

Error Scan: Scans the surface for errors

Temperature display

HD Tune Pro gives us accurate read, write, and access time results. It is now considered a must-have application for storage device testing.

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We shouldn't run into any issues today with the Samsung 840 EVO mSATA 120GB when it comes to read performance. This drive should actually be brilliant when reading both sequential and random data. On the sequential side: at QD1, we achieved an average read of 440 MB/s with the 64KB block size.

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When writing 64KB blocks, we see how write performance can drop off with sequential data. Let's look at the actual trace to see what's happening.

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Here we see Turbo Write caching the write, but unlike the 1TB model, the 120GB capacity size has a very small SLC like buffer area. When we get through the SLC area, the 64KB sequential write performance drops down to between 140 and 150 MB/s.

HD Tach - Sequential Performance after Random Writes

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In this test, we use the 128KB block size, and run the test after a consumer appropriate level of random writes. This is where things get funky. We didn't hit the drive very hard with random writes, but the performance still dropped below 50 MB/s for the final 1/3 of the test.

Benchmarks - AIDA64 Random Access Time

AIDA64 Random Access Time

Version and / or Patch Used: 1.60

Developer Homepage:

Product Homepage:

AIDA64 offers several different benchmarks for testing and optimizing your system, or network. The Random Access test is one of very few (if not the only), that will measure hard drives random access times in hundredths of milliseconds, as oppose to tens of milliseconds.

Drives with only one or two tests displayed in the write test mean that they have failed the test, and their Maximum and possibly their Average Scores, were very high after the cache fills. This usually only happens with controllers manufactured by JMicron and Toshiba.

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As expected, the read latency was very good on the Samsung 840 EVO mSATA 120GB. The TLC flash still manages to produce Marvell level read latency, as shown here with the Plextor PX-M5M.

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The write latency increases significantly once we get out of the Turbo Write area. This is an issue we've found on every low capacity Samsung SSD, going back to the 830.

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What it really comes down to is this: For normal day to day stuff like surfing the web, reading your online email, face-twit and such, the 120GB model will perform great. When you start downloading Outlook in the morning, and have 40+ messages, transfer movies or music to your EVO 120GB, or do anything that gets outside of Turbo Write, you will notice the slowdown with the drive running on its own.

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This is where RAPID Mode from the Magician software suite comes into play. If your system has 4GB of DRAM, RAPID will build a 1GB DRAM cache to give your storage system a larger buffer that is able to absorb the data, and feed it to the drive in steady doses. The result is a much smoother user experience.

Benchmarks - Anvil Storage Utilities

Anvil Storage Utilities

Version and / or Patch Used: RC6

So what is Anvil Storage Utilities? First of all, it's a storage benchmark for SSDs and HDDs where you can check and monitor your performance. The Standard Storage Benchmark performs a series of tests, you can run a full test, or just the read or the write test, or you can run a single test (i.e. 4K DQ16).

Anvil Storage Utilities is not officially available yet, but we've been playing with the beta for several months now. The author, Anvil, has been steadily updating the software on several international forums, and is adding new features every couple of months.

The software is used several different ways, and to show different aspects for each drive. We've chosen to use this software to show the performance of a drive with two different data sets. The first is with compressible data, and the second data set is incompressible data. Several users have requested this data in our SSD reviews.

0-Fill Compressible Data

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Incompressible Data

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The Samsung 840 EVO mSATA does not slow when working with incompressible data.

Read IOPS through Queue Depth Scale

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In the 1TB model review, I stated my personal notebook has a 2.5" EVO installed in it right now. The reason why is the low queue depth performance that the EVO products have. The 120GB mSATA model can hit over 10,000 4K IOPS at QD1. It would be rare to actually use that much performance under normal use, but the user experience increases when you do.

Scaling Write IOPS through Queue Scale

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The EVO mSATA 120GB also does well writing 4K data thanks to Turbo Write. Your day-to-day activities will run stutter free.

Benchmarks - CrystalDiskMark


Version and / or Patch Used: 3.0 Technical Preview

Developer Homepage:

Product Homepage:

Download here:

CrystalDiskMark is a disk benchmark software that allows us to benchmark 4K, and 4K queue depths with accuracy.

Key Features:

* Sequential reads/writes

* Random 4KB/512KB reads/writes

* Text copy

* Change dialog design

* internationalization (i18n)

Note: Crystal Disk Mark 3.0 Technical Preview was used for these tests, since it offers the ability to measure native command queuing at 4 and 32.

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By mSATA standards, the 840 EVO mSATA 120GB has solid 4K read delivery. The mSATA version is a little slower than the 2.5" EVO, but in many Ultrabooks, you don't have the option use one or the other. The 120GB model scales well when the queue depth increases.

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With nearly 140 MB/s of 4K write at QD1, the 120GB mSATA EVO will keep your random data moving at a fast pace. There isn't a lot of scaling when NCQ stacks up, but in most cases, regular users aren't going to multitask heavily, so it's not that big of an issue. SSDs are already amazingly quick compared to the HDDs they replace.

Benchmarks - PCMark Vantage Hard Disk Tests

PCMark Vantage - Hard Disk Tests

Version and / or Patch Used: 1.0.0

Developer Homepage:

Product Homepage:

Buy It Here

PCMark Vantage is the first objective hardware performance benchmark for PCs running 32, and 64 bit versions of Microsoft Windows Vista. PCMark Vantage is perfectly suited for benchmarking any type of Microsoft Windows Vista PC, from multimedia home entertainment systems and laptops, to dedicated workstations and high-end gaming rigs. Regardless of whether the benchmarker is an artist, or an IT Professional, PCMark Vantage shows the user where their system soars, or falls flat, and how to get the most performance possible out of their hardware. PCMark Vantage is easy enough for even the most casual enthusiast to use, yet supports in-depth, professional industry grade testing.

FutureMark has developed a good set of hard disk tests for their PCMark Vantage Suite. Windows users can count on Vantage to show them how a drive will perform in normal day to day usage scenarios. For most users, these are the tests that matter since many of the old hat ways to measure performance have become ineffective to measure true Windows performance.

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HDD1 - Windows Defender

HDD2 - Gaming

HDD3 - Windows Photo Gallery

HDD4 - Vista Startup

HDD5 - Windows Movie Maker

HDD6 - Windows Media Center

HDD7 - Windows Media Player

HDD8 - Application Loading

Just how much faster are SSDs? In many real-world application tests, eight to twelve times faster is a fair value compared to HDDs. The value changes depending on the application, but the increase in performance is significant. In many cases, SSDs are limited by the SATA III bus, while HDDs still perform within SATA II specifications. The SATA III limitations are why so many SSDs perform very close to each other at this time.

Benchmarks - PCMark Vantage - Drives with Data Testing

PCMark Vantage - Drives with Data Testing

For a complete breakdown on the Drives with Data Testing please read this article. You will be able to perform this test at home with the files provided in the article - full instructions are included.

- Brief Methodology

SSDs perform differently when used for a period of time, and when data is already present on the drive. The purpose of the Drives with Data testing is to show how a drive performs in these 'dirty' states. SSDs also need time to recover, either with TRIM, or onboard garbage collection methods.

Drives with Data Testing - 25%, 50%, 75% Full States and Dirty / Empty Test

Files needed for 60 (64GB), 120 (128GB), 240 (256GB)

60GB Fill - 15GB, 30GB, 45GB

120GB Fill - 30GB, 60GB, 90GB

240GB Fill - 60GB, 120GB, 160GB

Empty but Dirty - a test run just after the fill tests, and shows if a drive needs time to recover, or if performance is instantly restored.

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One way for SSD manufacturers to separate one product from another is to build a drive that works well, even when data populates the flash. We use the 50% of capacity market to judge performance in a used state. The Samsung 840 EVO mSATA is the new king of mSATA drives when it comes to performance with data on the drive. This used to be a low point for older Samsung SSDs, but Samsung has managed to build new products that put the company's drives in a leadership position.

Final Thoughts

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In years past, we worried about testing Samsung's smaller capacity SSDs, and I think Samsung worried about what we would come up with as well. Before RAPID, the smaller capacity drives with lower interleaving levels between the flash and the controller were an issue. RAPID (and to a smaller extent, Turbo Write) alleviated the issue. To put it in simple terms: the lower capacity Samsung SSDs are pretty good now.

When it comes to reading data from the drives, the 840 EVO mSATA products are leading the market. The EVO products are positioned as consumer SSDs, so most of these drives will end up in soccer mom Ultrabooks, or business notebooks/Ultrabooks. That's not really a bad place to be and with the new eDrive, and TCG Opal support. Business users can increase productivity, while still staying within company security policies, and if needed, it's even HIPPA compliant.

With the performance and feature set covered, that only leaves availability and the price. At the time of writing, the mSATA versions of EVO were not at any of the e-tailers we checked. Samsung expects e-tail availability just after CES, or the second week of January. The launch day MSRPs are very close to the 2.5" EVO products, so we expect discount e-tailers like Newegg, Tiger Direct, and so on to take a hit on margins, and put MSRPs in the rear view as early as a week after the launch.

The Samsung 840 EVO mSATA 120GB is a cost effective way to install best in class performance for a new Ultrabook. RAPID Mode, part of the free Magician software suite, does a good job of fixing any write latency issues, and leaves us with a great all around performer. While we don't talk about it much, Samsung's Data Migration software (also a free add-on) is a great way for mainstream users to clone an existing drive without a lot of technical knowledge. In this case though, you would need to do so without the aid of a USB adapter.

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