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Samsung SSD 840 PRO Series Review

Our Verdict

The Samsung SSD 840 PRO Series is the fastest SSD we've tested and can add more than hour of battery life to your notebook, making it our top pick.


  • Extremely fast
  • Low power usage can save battery life
  • 7mm height fits slim notebooks


  • Higher cost per GB than some competing drives

These days, you can find a good 128GB SSD for around $100 and a 256GB SSD model for $200, both of which will run circles around the fastest hard drive. However, not all solid-state drives are created equal. If you're willing to pay more, you can get significantly better performance and added flexibility with the Samsung 840 PRO. At a cost of $149 for 128GB and $269 for the 256GB capacity, Samsung's 840 PRO Series is the new king of SSDs, with blazing fast speeds, slim design and low power consumption.


Click to EnlargeThough you probably won't be looking at it after you install it, the 2.5-inch-long Samsung SSD 840 PRO Series has a subtle but attractive design: a dark gray metal chassis emblazoned with a light gray Samsung logo and an orange square on top.

At 7mm thick, the 840 PRO Series can fit into laptops with drive bays too slim for the average 9mm-thick SSD. For example, during our testing, we were able to install the drive in a ThinkPad X230 but unable to fit any 9mm drives into that notebook's slot. Even if your notebook currently has a 9mm- tall drive, the 7mm 840 PRO Series will fit into larger brackets.

Controller and Flash Memory

While most of today's SSDs use third-party controllers like the SandForce SF-2281, the 840 PRO is powered by Samsung's own MDX controller, which has three ARM Cortex R4 cores running at 300 MHz, along with a 512MB cache. The controller offers AES 256-bit Full Disk Encryption without affecting performance.

The 840 PRO uses speedy new 21-nanometer Flash memory with a 400Mbps Toggle NAND 2.0 interface, which should be faster than the 27nm Flash memory on last year's 830 series. Because of the speedy controller and memory, Samsung claims the 840 PRO can provide up to 100,000 random read and 90,000 random write IOPS (input/outputs per second).

Magician Software

Click to EnlargeSamsung bundles the 840 PRO Series with its Magician 3.2 utility suite and Samsung Data Migration software. Magician has a number of useful features, including a performance benchmark, a firmware updater and secure erase. Perhaps the most useful of these is the over provisioning tool, which allows you to set aside some of your SSD's storage space to be used for "garbage collection" and other processes that the drive uses to keep itself fast, even as you write and erase data. The manual recommends setting aside 7 to 10 percent of the space for this purpose.

The Samsung Data Migration tool offers a simple way to clone your old disk to your new 840 PRO Series drive. However, there are many freeware alternatives that provide similar functionality, including Macrium Reflect Free, which we used in our testing.

The Competitors

To see how the Samsung SSD 840 PRO Series stacks up, we ran it through a series of benchmarks and compared the results with those from two competitors: the $236 OCZ Vertex 4 (256GB), which uses a 400-MHz Indilinx Everest 2 controller, and the $200 Intel SSD 335, which relies on the popular SanForce SF-2281 controller. To show the performance delta between the 840 PRO Series and a typical hard drive, we also ran a 500GB, 7,200 rpm Hitachi hard drive through the tests.


Click to EnlargeIn order to get a sense of what the Samsung SSD 840 PRO Series is capable of under ideal conditions, we ran CrystalDiskMark 3.0.2. The test measures read and write speeds using a 1000MB file, transferring it in sequential, 512K and 4K block sizes.

With the file transferring as one sequential block, the Samsung SSD 840 PRO Series delivered blazing fast read/write speeds of 490.6 and 462.7 MBps, respectively, blowing away the OCZ Vertex 4 (388.7/435.2 MBps) and tying the Intel SSD 335 for reads (490.6 MBps) but smoking its writes (325.9 Mbps).

The SSD 840 PRO Series dominated in the 512K-block size, providing 30.1 MBps reads and 418.5 MBps writes. Neither of its competitors even cracked 400 MBps in reads, and Intel provided a relatively weak 291.1 MBps in writes.

Considering how many small pieces of data you transfer back and forth during a typical session, small 4K reads and writes might be the most important. On standard 4K transfers, which always have the slowest speeds, the Samsung SSD 840 PRO Series notched a reasonable read rate of 27.8 MBps, which barely edged out the OCZ Vertex 4 (26 Mbps). However, the Samsung registered a somewhat mediocre write rate of 51.2 Mbps, as compared with 62.2 MBps on the Vertex.

Fortunately, like all modern SSDs, the 840 PRO Series use NCQ (Native Command Queuing) to dramatically speed up 4K transfers. With a queue depth of 32, the 840 PRO Series again showed its dominance, returning read/write rates of 370.7/362.8 Mbps. These results comfortably beat the OCZ Vertex 4 (316.6/298.3 MBps) and Intel SSD 335 (214.8/276.2 Mbps).

IOPS (Input/Output Per Second)

Click to EnlargeThe higher its IOPS, the more work an SSD can do at one time. That's why most vendors advertise their drives' maximum read and write IOPS. However, low latency is also important, because the faster your drive starts executing a command, the sooner it can be finished and move on to the next one.

We used IOMeter to measure raw read and write IOPS, configuring the software on our testbed to measure both random and sequential 4K reads and writes.

DriveRead IOPS RandomWrite IOPS RandomRead LatencyWriteLatency
Samsung 840 Pro79,01035,7000.040.89
OCZ Vertex 4 64,35029,3610.491.08
Intel SSD 33525,22916,7191.21.9

The Samsung SSD 840 PRO Series smoked its competitors with a random read IOPS of 79,010 and a random write IOPS of 35,700; that's with latencies of just 0.4 and 0.9 milliseconds, respectively. The Vertex 4 managed just a 64,350/29,361 IOPS score, while the Intel SSD 335 produced weak marks of 25,299 read and 16,719 write IOPS.

DriveRead IOPS SeqWrite IOPS seqRead Latency SeqWrite Latency Seq
Samsung 840 Pro76,21978,3080.410.41
OCZ Vertex 4 64,54773,0740.490.43
Intel SSD 33573,60553,4780.430.59

While the Intel and OCZ drives did considerably better on the sequential read and write tests, the Samsung SSD 840 PRO Series still offered the best performance, with a read and write rate of 76,219 and 78,308 IOPS, respectively. All three drives had similar read latency numbers, but in write latency, the Intel SSD 335 was 50 percent slower than the 840 PRO Series.

File Copy Tests

DriveMultifile Copy (sec)Single File Copy (sec)
Samsung 840 Pro0:250:15
OCZ Vertex 40:330:20
Intel SSD 3350:340:19
Hitachi 7,2002:371:10

To find out how quickly the Samsung SSD 840 PRO series copies files, we timed both a single 3.1GB transfer and a 4.97GB multi-file operation. With a multi-file time of just 25 seconds and a 15-second single-file transfer time, the 840 PRO Series bested the Intel and OCZ drives by 20 to 30 percent.

Zip Tests

Few individual tasks tax your storage system like compressing or uncompressing a large group of files, because the drive must both read and write a lot of data at the same time. To see how well Samsung SSD 840 PRO Series can handle this burden, we zipped and unzipped a 4.97GB group of mixed media files.

DriveZip Time (mm:ss)Unzip Time (mm:ss)
Samsung 840 Pro2:492:19
OCZ Vertex 42:492:23
Intel SSD 3352:502:24
Hitachi 7,2004:063:43

While the zip times were nearly identical on all three SSDs, the Samsung SSD 840 PRO was 4 to 5 seconds faster when unzipping.

Single Application Open Tests

DriveAdobe Reader (sec)Excel (sec)Firefox (sec)Photoshop (sec)Word (sec)Average Open (sec)
Samsung 840 Pro3.
OCZ Vertex
Intel SSD 3353.
Hitachi 7,2007.76.33.624.71.98.8

There are few computing experiences more frustrating than sitting and waiting for a program or file to open. To see how quickly the Samsung SSD 840 PRO Series drive can launch apps, we recorded open times for five typical applications: Adobe Reader opening to a 500-page PDF, Excel 2010 opening to a 6.5MB spreadsheet, Firefox 17 opening to a blank page, Photoshop CS6 opening to a 400MB TIF file, and Word 2010 opening to a blank document.

As with the synthetic and file copy tests, the Samsung SSD 840 PRO Series was noticeably faster than its competitors, providing an average launch time of just 2.8 seconds across all five programs, while the OCZ Vertex 4 and Intel SSD 335 offered average times of 3.6 and 3.7 seconds, respectively. The difference was most pronounced on the Photoshop open test, which the 840 PRO Series completed in just 6.9 seconds, versus 11 and 10.7 seconds on the OCZ and Intel drives. The 7,200 rpm hard drive took at least twice as long to open every application as the 840 PRO Series did.

Multitasking: App Opens Under Stress

DriveAdobe Reader (sec)Excel (sec)Firefox (sec)Photoshop (sec)Word (sec)Average Open (sec)
Samsung 840 Pro4.33.22.412.20.64.5
OCZ Vertex
Intel SSD3.83.82.919.01.26.2

To see how well the Samsung SSD 840 PRO Series can multitask, we performed the same app open tests, but this time with a huge file zip operation going on in the background. Under these stressful conditions, the Samsung SSD 840 PRO Series outperformed the OCZ and Intel drives by opening the applications under stress in an average of 4.5 seconds, compared with 5.9 and 6.2 seconds for the Vertex 4 and Intel SSD 335, respectively. The 840 PRO Series opened Photoshop under stress in a quick 12.2 seconds, while the Vertex 4 and Intel SSD 335 took 18.7 and 19 seconds. Note that the hard drive choked so badly that we couldn't get accurate numbers for most programs.

Power Consumption and Battery Life

Click to EnlargeSamsung touts the SSD 840 PRO Series' low power consumption of .068 watts when active and .042 watts when idle, which is much lower than the previous-generation 830 Series' power consumption of 0.24 watts active/0.14 watts idle. Because of the lower power consumption, the company claims that you'll be able to get significantly more battery life than with other SSDs.

During our tests, however, the drive's endurance was not significantly longer than its predecessor. When we installed the 840 PRO Series in a ThinkPad X230 with 6-cell battery, the notebook lasted 8 hours and 32 minutes, an hour and a half longer than the 6-hour and 56-minute time it got with its default hard drive, but only 14 minutes longer than it endured with last year's 830 Series. Our battery test simply surfs the Web, so perhaps we would have seen a bigger difference with a more hard-drive-intensive workload.


The Samsung 840 Pro Series is available in four capacities. The 64GB version sells for around $100, the 128GB currently retails for $150 and the 256GB version that we reviewed clocks in at $270. The high-capacity 512GB model sells for $600.


Click to EnlargeWithout a doubt, the Samsung SSD 840 PRO Series is the fastest SSD we've ever tested, providing significantly higher speeds in real-world tasks than its competitors. For users of ultraportable laptops and Ultrabooks, the drive's 7mm height alone makes it a compelling choice, while the low power consumption can significantly extend battery life. It's not the cheapest drive on the market, but if you want the best, the Samsung SSD 840 PRO Series is the top SSD choice right now.

Tech Specs

Capacity128GB / 256GB
Company Website
Read/Write SpeedUp to 530MB/s
Rotational SpeedN/A
Seek TimeUp to 390MB/s
Storage TypeSSD
Weight.15 lb