Samsung 840 Evo review: Finally, an SSD that has almost everything Part II
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.
Rapid mode uses part of the system's memory (RAM) to further boost the 840 Evo's performance.
(Credit: Screenshot by Dong Ngo/CNET)
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.
Cost per gigabyte (in dollars, based on street pricing at time of review)(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.
Internal hard drive data transfer (in MBps)(Longer bars indicate better performance)
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.