Samsung 840 120GB SSD Review

The 120GB Samsung 840 Series SSD features the powerful 8-channel MDX controller and TLC NAND. While this value SSD comes at a very good price, it also features much lower speeds than its larger capacity brethren. We put this value SSD through our suite of steady state tests to see if it can pass muster.



It seems that we were right to withhold the Silver status from the 120GB TLC product when awarding the 250 and 500GB versions with high marks. This 120GB TLC SSD simply doesn't live up to the reputation that we have come to expect from the Samsung 840 series.

While we have not tested the 120GB Samsung 840, we have reservations about lumping the 120GB capacity Samsung 840 into our award category, simply due to technical limitations imposed upon it.

When paired with the right NAND, or even enough of a lower quality NAND such as TLC, the MDX controller at the heart of this SSD can provide class-leading performance. Make no mistake, Samsung is currently the 800lb gorilla in the SSD market, but the Samsung TLC 120GB Model 840 is its Achilles’ heel.

Samsung did not bring a smaller capacity than 120GB to market simply because the TLC NAND could not provide the endurance or performance to create a sustainable product. The 120GB version limps in at acceptable for some, but by our estimation falls far short of delivering performance that would be suitable for a normal consumer.

We run a wide gamut of tests here at [H]ardOCP simply because some tests can reveal certain characteristics of an SSD that others will not. Interpreting and considering all results helps us to draw the most well-rounded opinion of the storage device in question.

The results of our latency testing initially raised the red flag. We knew that we were going to encounter slow write speeds with this SSD, but what we did not expect was to receive abysmal maximum read and write latency. Latency spikes of this nature are undoubtedly going to lead to interruptions in the flow of computing for users. SSDs with appreciably lower maximum latency can still experience the occasional hiccup, but with ranges of up to 67ms (three times higher than the nearest competing SSD) there is guaranteed to be laggy performance in many scenarios. Users will become accustomed to staring at the little blue spinning circle with this SSD in their system.

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The reason that we test latency separately from PCMark Vantage is due to Vantage not picking up appreciable differences in latency between storage devices. This test shows the maximum performance available in each scenario, but is weighted heavily to favor read speed in its overall score. This explains the reason that the 120GB Samsung 840 performed well in a few read-based tests and managed to pull off a high score. PCMark 7 tends to be more sensitive to latency QoS, and the score for the 120GB 840 was lower than the rest of the field in that suite of tests.

The slow sequential speed of the SSD will make simple procedures, such as copying pictures and videos, long drawn out affairs. Bear in mind that some 5400rpm HDDs can write at initial speeds of 140MB/s, and sustain a speed of 80-90MB/s. The fact that the 130MB/s that this SSD provides is even in the range of a 5400rpm HDD speaks volumes.

Endurance does become a concern with this capacity point, falling in at 3.5-4 years of light usage. For many users this simply would not be enough endurance for their use.

Users looking for a 120GB SSD would be best suited to stick with an MLC product, period. We do continue to highly recommend the 250GB and 500GB TLC Samsung 841 SSDs for typical consumer workloads.

One of the reasons that many pay so much more money per GB is the exponential speed that SSDs provide. While the $99 price point of the 120GB 840 might be tempting, its low performance might remove the motivation for a consumer to trade off so much capacity for this product.

The worst aspect is the extreme amount of read degradation that this SSD suffers once it reaches steady state. The read speed of the 120GB 840 is supposed to be its most redeeming quality, but once in steady state it dropped to the bottom of our charts. Taking away the one advantage of this drive leaves us with nothing more to say.

At the time of publishing the 120GB TLC Samsung 840 is $99.85, the Kingston SSDNow V300 120GB retails for $100.94, the 128GB Samsung 840 Pro is $139.00, the 128GB OCZ Vector SSD is available for $134.15.

The 240GB Intel 335 is $192.99, the Kingston SSDNow V300 240GB retails for $209.99, the 250GB TLC Samsung 840 is $179.96, the 256GB Samsung 840 Pro is $224.55, the 256GB OCZ Vector is retailing for $238.99.

The 500GB TLC Samsung 840 is an astounding $363.58, the 512GB Samsung 840 Pro is $496.79, the 512GB OCZ Vector retails for $543.17.

The Bottom Line

While we continue to recommend higher capacity Samsung TLC Model 840 SSDs, the TLC-equipped 120GB 840 Series SSD is simply not a good option for consumers. 3.5 to 4 years of projected light use is an endurance concern that users would be advised to watch closely if they were to purchase this SSD. Slow write speeds across the board in tandem with poor read and write maximum latency performance should overcome any temptation for saving a few bucks with this value SSD.

The read speed of the 120GB Samsung 840 SSD also fell tremendously when we tested in steady state conditions. This removes the one advantage that the product has, making it more suited for sitting on the shelf than setting in your computer.

Users looking for a 120GB or less capacity SSD should stick with MLC products.