Why You Can Trust CNET Samsung 840 Evo review: Finally, an SSD that has almost everything
The Samsung 840 Evo offers great performance, top capacity, and a helpful software bundle, and doesn't dig a hole in your wallet. What else can you ask for in a solid-state drive?
There are three important things you should keep in mind when buying a solid-state drive: capacity, performance, and pricing. And the new Samsung 840 Evo makes things easy by offering them all, and more.
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The Good
The Bad
The Bottom Line
The new drive is a replacement for Samsung's previous
At the current price of well under $1 per gigabyte -- the 1TB capacity costs just $650, or about 65 cents per gigabyte -- the Samsung 840 Evo is the best deal on the market now, ranking at the top of the current best SSD list. If you're looking for an SSD to upgrade your computer's hard drive with or want to upgrade your existing SSD to a larger-capacity drive, the 840 Evo is as good as it gets.
Design
The Samsung 840 Evo looks the same as the older 840 Series, but now comes in dark gray. The drive supports the popular 7-millimeter, 2.5-inch design and features the latest SATA 3 (6Gbps) standard. It also works with previous versions of the SATA standard.
| Drive type | 7mm-thick, 2.5-inch standard internal drive |
| Connector type | SATA 6Gbps (compatible with SATA 3Gbps and SATA 1.5Gbps) |
| Capacities | 120GB, 250GB, 500GB, 750GB, and 1TB |
| Review capacity | 750GB |
| Controller | Samsung MEX controller |
| NAND flash memory | 1x nm Samsung Toggle DDR 2.0 |
| Sequential read: | Up to 540MBps |
| Sequential write: | Up to 520MBps (250GB/500GB/750GB/1TB), and up to 410MBps (120GB) |
| 4KB Random read (QD1): | Up to 10,000 IOPS |
| 4KB Random write (QD1): | Up to 33,000 IOPS |
| 4KB Random read (QD32): | Up to 98,000 IOPS (500GB/750GB/1TB); up to 97,000 IOPS; (250GB); up to 94,000 IOPS (120GB) |
| 4KB Random write (QD32): | Up to 90,000 IOPS (500GB/750GB/1TB); up to 66,000 IOPS (250GB); up to 35,000 IOPS (120GB) |
| Encryption | AES 256-bit Full Disk Encryption (FDE) |
| Weight | 1.9 ounces |
| Reliability | MTBF: 1.5 million hours |
| Warranty | 3 years limited |
The drive is available in five capacities, 120GB, 250GB, 500GB, 750GB, and 1TB, all of which come with the Samsung Data Migration Tool and Samsung Magician Software included. The former is an advanced cloning program that helps you move data from one drive to another without having to reinstall the operating system or software; and the latter is a set of powerful tools for customizing the drive.
To help make life even easier for upgraders, the drive is also available in a Desktop Kit version for the 120GB and 250GB capacities, and a Laptop Kit version for the 250GB and 500GB capacities, respectively costing $15 more and $10 more than if you buy just the SSD itself. The Desktop Kit includes a drive bay converter caddy, a 2.5mm spacer to bring the thickness of the drive to the 9.5mm standard, a CD of software, and a USB 3.0-to-SATA adapter. The Laptop Kit consists of just the software, the spacer, and the USB 3.0-to-SATA adapter.
With either of these kits, folks can quickly clone their computer's existing hard drive to an 840 Evo, without having to get extra equipment. The software CD contains the above-mentioned Samsung Data Migration Tool and Samsung Magician Software, which can also be downloaded from Samsung's Web site.
Useful software, flexible configuration
Like previous Samsung SSDs, the 840 Evo doesn't come with overprovisioning out of the box. Instead you can turn this feature on and off using the Samsung Magician Software. Overprovisioning is a feature that uses part of an SSD's storage space to enhance the drive's performance. Thanks to this, the 840 Evo offers the flexibility to choose between maximum speed or capacity.
Using the Samsung Magician Software, you can also check the SSD's health status and securely erase its data, or tune up the operating system settings to maximize the drive's speed and endurance.
Modern and performance-oriented software and hardware features
There are a couple of things that help make the 840 Evo so fast.
Firstly, Samsung Magician now offers a new function, introduced in the 840 Evo, called Rapid mode, which can be turned on or off with a click. When on, Rapid automatically uses part of the host computer's system memory (RAM) as cache to further boost the drive's performance. Depending on the available RAM, Rapid uses between 500MB and 2GB for this purpose. In my test, Rapid indeed significantly improved the drive's performance.
Secondly, in the area of hardware, the new drive uses a new and improved Samsung MEX controller, which is based on the three-core MDX controller used in the 840 Pro, and its fast Toggle DDR 2.0 NAND flash memory. The drive also has improved firmware to deliver significantly faster performance than the 840 Series.
And finally, the 840 Evo supports a feature called TurboWrite Technology, which, depending on the capacities involved, offers double or triple the sequential write performance of the 840 Series. With Turbo Write, part of the solid-state drive is made of single-layer cell (SLC) NAND flash memory, the type of NAND used mostly in high-end enterprise SSDs. This part is used as a buffer for writing. Basically, data gets written on the buffer first and will then be moved to other parts of the SSD when the drive becomes idle. Since in real-world usage an SSD is idle most of the time, Turbo Write works very effectively.
And speaking of idle, the 840 Evo uses very little power when not in use, just 0.045 watt, compared with the 0.5 watt of a regular hard drive or certain SSDs. (The 840 Series uses 0.046 watt.) This makes the new drive a great fit for laptop users.
In my trials, the Samsung 840 Evo worked well with Windows, Linux, and Mac OS X. For better performance it's recommended that you use the latest version of the OSes that support the TRIM command, such as Windows 7 and Mac OS 10.6 or later. Note, however, that the drive's bundled software only works with Windows.
Cost per gigabyte and warranty
Pricing is always the biggest concern when it comes to SSDs, but the 840 Evo delivers. The drive's five capacities of 120GB, 250GB, 500GB, 750GB, and 1TB cost $110, $190, $370, $530, and $650, respectively. Except for the 120GB capacity, which costs about 92 cents per gigabyte, these are all less than 80 cents per gigabyte. And again, the 1TB capacity is even less per gigabyte, at just 65 cents.
It's fair to say that the 840 Evo brings SSD pricing lower than ever. It's likely its price will get even lower the longer the drive is on the market.
It's worth noting that the 840 Evo comes with only a three-year warranty, not the five-year of the 840 Pro and some other high-end drives. But three years is rather standard for a drive that's categorized as entry-level.
(Shorter bars indicate better performance)
Performance
I actually compared the 840 Evo against other high-end SSDs and it was impressive. The test computer took just about 10 seconds to boot up and about half of that to shut down. The drive also helped the machine resume from sleep-mode almost instantly. Applications, including heavy ones, such as games, also took much less time to load than when the computer was running on a hard drive.
The Evo offered much faster write speed than read speed, scoring 267MBps for writing and 184MBps for reading, in a straightforward data-copying test. When working as a main storage drive hosting the operating system and performing both writing and reading small files at the same time, the drive managed 257MBps. All of these speeds were really fast compared with the other drives' performance.
Yet the drive was even faster with Rapid turned on, scoring 289MBps for writing, 193MBps for reading, and an impressive 378MBps combined, the best I've seen
With PCMark 8, the 840 Evo scored 4,967 Storage points, and 4,990 points with Rapid turned on. Its reading score was lower than other high-end drives', but the 840 Evo was among the fastest in the other categories.
(Longer bars indicate better performance)
 | As secondary drive (read only) | | As secondary drive (write only) | | As OS drive (read and write) |
(Longer bars indicate better performance)
| Storage | | Work | | Home |
The new SSD also increased the battery life of a computer by about 25 minutes compared with a regular 7,200rpm laptop hard drive, in my anecdotal testing.
Conclusion
With fast overall performance, affordable prices, and a top storage capacity of 1TB, the Samsung 840 Evo has almost everything you'd look for in an internal storage device. What could be improved, namely the slightly slow sequential read speed and the relatively short three-year warranty, are just a minor shortcomings that don't change the fact that the drive is the best deal on the market now. The new drive opens up a new and exciting chapter in which solid-state drives are comparable to regular hard drives in terms of capacity and even pricing, while remaining so much faster in performance.