Last week, Samsung announced the new 840 Evo SSD series to replace the existing 840 series. The write speeds should be significantly higher, but the affordable price remains the same. We tested the entire series, consisting of 120GB, 250GB, 500GB, 750GB and 1TB models.
The current 840 series was the first to use triple level cell (TLC) memory. In TLC memory, three bits are saved to each memory cell. The more common type is MLC (multi level cell) where two bits are stored per cell. That means Samsung only needs two-thirds the number of memory cells for the same amount of storage. Fewer chips mean lower production costs.
Along with the fact that Samsung has its own controller and its own flash, it made it possible to make the 840 very affordable. A Samsung 840 250GB currently costs an average of £140, and it is possible to find even cheaper deals. These price levels are challenging for the competition. The affordability and unparallelled performance of the 840 Pro series have helped Samsung increase its market share for SSDs significantly.
TLC memory, however, has the drawback of taking longer to write to, which led to relatively slow write performance for the 840 SSDs. Samsung came up with a clever solution for the new 840 Evo series that should increase the write speed. For TLC SSDs, Samsung guarantees a lifespan of at least 1000 writes, but our tests indicate you can expect much more. For normal consumer applications, TLC memory is more than reliable enough.
The 840 Evo SSDs are set to replace the 840 SSDs, which will soon be end-of-life. Samsung's high-end SSDs, the 840 Pros, will not yet be replaced, but the new Evos should come closer in terms of performance.
The Samsung 840 Evo SSDs have '10nm class' ToggleNAND TLC flash memory, which actually turns out to be 19nm flash chips. You can read the rest of Samsung 840 Evo SSD preview on Hardware.info.