The Samsung 870 QVO (1TB & 4TB) SSD Review: QLC Refreshed

[tarekma7]

A year and a half ago, Samsung introduced the first consumer SATA SSDs to use QLC NAND flash memory, squeezing an extra bit into each memory cell, yielding the 860 QVO to join the existing lineup of 860 EVO and PRO. Samsung's second-generation QLC NAND is now ready, and the 870 QVO is the first 870 model to be launched.

The industry put a lot of effort into preparing for the arrival of QLC NAND: beefing up error correction to compensate for lower write endurance, and tuning cache algorithms on consumer drives to forestall dealing with lower performance after SLC caches run out. But in spite of all the work it took to make QLC SSDs viable, they haven't made much of a splash and definitely aren't displacing TLC from the market yet.

The new Samsung 870 QVO SSDs arrive into a market landscape that doesn't look all that different to what the 860 QVO faced at the end of 2018. Samsung is no longer the only brand selling consumer SATA SSDs with QLC NAND, but it's not a big club. Most of the other QLC SATA drives are so low-end that the manufacturers won't commit to using any particular memory inside, and they're using whatever is cheapest at the moment. Some months, there's more to be saved by going with a DRAMless controller and TLC NAND that fell off the back of a truck, rather than using Samsung's strategy of pairing theoretically cheaper QLC NAND with a solid controller.

QLC NAND has had a bit more of an impact in the NVMe SSD market, where a few more brands are experimenting with using QLC to make big drives cheaper, rather than simply making cheap drives even cheaper. That's the same goal that Samsung had for the 860 QVO and now the 870 QVO: bringing multi-TB SSDs into the mainstream. Samsung's most visible contribution to that goal will be the introduction of the first 8TB consumer SATA SSD: the 8TB 870 QVO. That model is due to arrive a little bit later in August, and we don't have a sample yet. Today, we're looking at the 1TB and 4TB capacities of the 870 QVO.

The Samsung 870 QVO is an incremental update to the 860 QVO. The QLC NAND has been updated from Samsung's 64-layer V-NAND to their 92-layer V-NAND. For their NVMe product line, this change produced the 970 EVO Plus as a successor to the 970 EVO without even updating the controller, and the 970 PRO didn't get updated at all. The 870 QVO does bring a controller update, replacing the MJX with the MKX in Samsung's long line of SATA SSD controllers. Samsung hasn't disclosed any particular enhancements to their controller or firmware architecture, and we suspect this iteration is a more minor update than the last one. We know that the older MJX controller was already capable of supporting 8TB drive capacities, so that wasn't the driving force for this controller update.

More info HERE