Reviews: Solid-State Drive Reviews

REVIEW / Samsung 840 Evo 250 GB, Faster Than The 120 GB

Neck-and-neck with the 840 Pro!

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Pierre-Jean Alzieu Published on October 2, 2013
Translated by Hugh Ehreth


  • Capacity
  • Cache 512 MB
  • Read speed 540 MB/s
  • Write speed 410 MB/s
  • 4K random read 97000 IOPS
  • 4K random write 66000 IOPS
Last month we reviewed the 120 GB version of the Samsung 840 Evo solid-state drive, and now we're looking at the 250 GB model to see if Samsung's claims that it has faster write speeds are true. According to Samsung, it can reach 520 MB/s, which would rival the fastest SSDs out there. To keep costs down, the company opted for TLC NAND, a type of flash memory that's economical, but less reliable over time (1,000 cycles) than the MLC NAND found in the 840 Pro (3,000 cycles, not to be confused with the 840).


Samsung 840 Evo 250 GB

The 250 GB model has the same body as the 120 GB. It's a thin (7 mm), lightweight (44 grams) 2.5" drive with a SATA III interface (6 Gbps)... all good things for a laptop. It has an MEX Controller with three ARM Cortex-R4 cores clocked at 400 MHz and uses a 19 nm process.

But one thing's different: the buffer system (TLC NAND simulated as SLC, with one bit instead of three) is twice the size in order to boost the speeds. The 250 GB has a 6 GB buffer, whereas the 120 GB has just 3 GB.

Samsung 840 Evo 250 GB

Samsung also gave it a built-in temperature sensor that allows the drive to sense when it's overheating and then limit the speeds until the drive cools down.

Data transfer speeds

Samsung 840 Evo 250 GB

File transfers (photos, videos...): sequential speeds

Samsung's right about the speeds. The 840 Evo 250 GB reads at 504 MB/s and writes at 492 MB/s, rivalling last year's Samsung 840 Pro, our current all-time reference.

However, as with the 120 GB, you can only reach these speeds with files that are smaller than the buffer. When you transfer files larger than 6 GB (such as a Full HD movie), the speeds drops to nearly 100 MB/s.

Samsung SSD Magician

Samsung 840 Evo 250 GB
Samsung Magician (results not from the 840 Evo 250 GB)

Also in the box is a CD for SSD Magician, or you can download it from Samsung's website. This is an intuitive programme that offers a variety of functions, such as system info, benchmarking, SSD/OS performance optimisation, firmware updates, secure deletion and over-provisioning.

In the CD you'll also find a cloning programme for transferring data from another drive to the SSD. It's quick and easy to do, perfect for when you want to replace your old drives!


  • 504 MB/s reads on large files
  • 492 MB/s writes on large files
  • Lightweight, perfect for a notebook
  • Samsung SSD Magician software is handy and intuitive


  • TLC flash memory is theoretically three times less long-lasting than MLC


The 250 GB model of the Samsung 840 Evo gets faster writes than the 120 GB, putting it neck-and-neck with the fastest SSDs on the market. However, with TLC NAND—which doesn't last as long as MLC—and only a three-year warranty, we can't give it all five stars.
4 Samsung 840 Evo 250 GB DigitalVersus 2013-10-02 12:23:00
Compare: Samsung 840 Evo 250 GB to its competitors
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