Samsung SSD 840 EVO
SSDs today are already fast enough that there isn’t much to separate the mainstream and high-end models. This isn’t to say high-end SSDs aren’t worth the premium, but rather, mainstream SSDs offer more value for the money for the average user. This is where the Samsung SSD 840 EVO comes in.
In order to bring down the costs of its SSDs, Samsung went with a TLC (or Triple-Level-Cell) NAND storage design. As its name implies, TLC NAND stores three bits of data per cell, translating to eight possible voltage states and a higher memory density. What this means is that more dies can be harvested from a single wafer, thus reducing manufacturing costs.
Unfortunately, with eight voltage states to check, the use of TLC NAND is often associated with lower levels of performance and poorer drive endurance. However, users should not worry too much about this because even if you write 30GB of data to the drive each day, the 840 EVO is estimated to have a lifespan of over 15 years. By that time, your system would most definitely be obsolete.
To address the issue of performance however, Samsung has implemented something called TurboWrite technology to boost write performance by dedicating a small portion of its TLC NAND to work as an SLC write buffer. Thanks to this technology, the Samsung SSD 840 EVO actually commands a very decent performance despite its mainstream positioning.
In our tests, we found that it could match and even outclass high-end MLC NAND drives in some benchmarks and workloads. It only lost its competitive edge at workloads with high queue depths, when its TurboWrite cache was either insufficient or exhausted. That said, there is very little in everyday computing tasks that would stress a drive out as much, so for most users the Samsung SSD 840 EVO’s performance should be more than sufficient.
If you need more performance, the SSD 840 EVO also features RAPID caching technology. Disabled by default, RAPID mode on the drive will enable it to make use of spare CPU resources and system memory to cache frequently used data to further boost performance. Surprisingly, the gains reported with RAPID mode enabled were very significant as transfer speeds easily doubled or more. However, it does come with some risks as its cache writes to your system memory first before transferring to the SSD. System memory is volatile, so there is the off chance that you might lose your data should a power outage occur before it is able to transfer this data onto the SSD.
At $259 for the 250GB variant, the Samsung SSD 840 EVO costs substantially more than its closest competitor in this segment - the Crucial M500 - even if it comes very close to the one dollar per gigabyte mark. But considering the performance gains of the SSD 840 EVO over the M500, we feel that the premium is well justified.
As it is, unless endurance is of the utmost concern to you, the Samsung SSD 840 EVO offers the best performance in this price bracket and comes highly recommended.