Review of the Samsung 870 QVO SSD (1TB and 4TB): QLC updated

A year and a half ago, Samsung introduced the first consumer SATA SSDs that used QLC NAND flash memory, squeezing an extra bit into each memory cell, allowing the 860 QVO to join the existing line of 860 EVOs and PRO. Samsung’s second-generation QLC NAND is ready, and the 870 QVO is the first 870 model to be released.

The industry went to great lengths to prepare for the arrival of QLC NAND: reinforcing error correction to compensate for lower write resistance and adjusting cache algorithms on consumer drives to avoid slower performance after SLC caches are exhausted . But despite all the work it took to make QLC SSDs viable, they haven’t made much of an impact and they’re definitely not pushing TLC out of the market yet.

The new Samsung 870 QVO SSDs reach a market landscape that doesn’t look all that different from what the 860 QVO faced in late 2018. Samsung is no longer the only brand selling consumer SATA SSDs with QLC NAND, but it’s not a great club.Most of the other QLC SATA drives are low-end so manufacturers won’t commit to using any particular memory indoors, and they’re using whatever is cheaper right now. Some months, there’s more to save with a DRAMless controller and TLC NAND that fell off the back of a truck, instead of using Samsung’s strategy of theoretically cheaper QLC NAND pairing with a solid controller.

QLC NAND has had a bit more impact on the NVMe SSD market, where a few more brands are experimenting with using QLC to make big drive cheaper, instead of just making cheap units even cheaper. That’s the same goal that Samsung had for the 860 QVO and now the 870 QVO: bringing multi-TB SSDs to 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 expected to arrive a little later in August, and we don’t have a sample yet. Today, we are looking at the 1TB and 4TB capabilities of the 870 QVO.

Samsung MKX driver and DRAM LPDDR4

The Samsung 870 QVO is an incremental upgrade to the 860 QVO. The QLC NAND has been upgraded from Samsung’s 64-layer V-NAND to its 92-layer V-NAND. For its NVMe product line, this change produced the 970 EVO Plus as a successor to the 970 EVO without even updating the driver, and the 970 PRO was not updated at all. The 870 QVO brings a driver update, replacing the MJX with the MKX in Samsung’s long line of SATA SSD controllers. Samsung has not revealed any particular enhancements to its controller or firmware architecture, and we suspect this iteration is a smaller update than the previous one. We know that the previous MJX controller was already capable of supporting 8TB disk capacities, so that was not the driving force behind this driver update.

Samsung continues to provide more detailed performance specs than any other consumer SSD provider. The large numbers on the top line that everyone reports are hardly worth mentioning for a SATA drive; almost any unit can saturate the 6 Gbps interface under ideal conditions, with random or sequential reads or writes at a queue depth high enough. Samsung goes the extra mile to provide performance specs on queue depth 1 and performance after the SLC cache runs out. Some of those numbers look pretty brutal: Sequential write speeds drop to just 80MB / s for the 1TB model, and even random reads are considerably slower when accessing QLC data instead of cache. SLC. But overall, these specs are very similar to the 860 QVO. The random write performance on QD1 seems to have been somewhat successful, but elsewhere the performance of the 870 QVO is rated as equal to or slightly better than its predecessor.

The 870 QVO product line still starts at 1TB, the minimum size required for 8 controller channels to work when using 1024Gbit NAND arrays. That smaller capacity model comes with some significant performance deficits relative to multi-TB models, in the same way that 256GB TLC drives lag behind their larger counterparts, or 512GB capacities for NVMe SSDs. high perfomance. The most notable limitations of the 1TB 870 QVO are the post-cache write speed of 80MB / s compared to 160MB / s, and the cache size being nearly halved. Taken together, that means the 1TB model is more at risk of exhibiting unacceptable performance when the SLC write cache runs out, but at 42GB, this model’s cache can still handle more writes than many users on a full day of desktop use.

Samsung’s warranty for the 870 QVO is 0.3 units written per day for 3 years. This is comparable to many low-end consumer TLC units and a step up from most other consumer QLC units that are rated for 0.1 to 0.15 DWPD (sometimes during a 5-year warranty period, but that’s still fewer total writes than the 870 QVO is qualified for).

Introductory MSRPs for the 870 QVO are reduced from what the 860 QVO debuted with $ 50 off 2TB and $ 100 off 4TB. But that simply puts the launch MSRP of the 870 QVO on par with current street prices for the 860 QVO. And because it’s Samsung, the price isn’t low enough to rule out the comparison to conventional SATA TLC SSDs and entry-level NVMe SSDs, especially for the lower capacities.

In a way, that’s good for this review, because the 870 QVO doesn’t have much direct competition in the form of other large SATA QLC drives. Most SSDs that are considerably cheaper than the 860/870 QVO are DRAM-free SSDs, generally TLC but occasionally QLC. The cheapest entry-level NVMe SSDs are DRAMless with TLC or use QLC with a more conventional controller.

For this review, we are comparing the 870 QVO with the following:

• The immediate predecessor of the 870 QVO, the 860 QVO
• ADATA Ultimate SU750 and Patriot P200, two different SATA TLC drives without DRAM. The SU750 uses a Realtek controller and the 2TB P200 used a Maxio controller, both budget options.
• The Crucial MX500 and Samsung 860 EVO as conventional SATA SSDs with TLC NAND. The MX500 has always been one of the most affordable conventional SATA SSDs from a major brand, and the 860 EVO generally marks the most that makes sense to pay for SATA SSDs, and the money would be better spent on a good NVMe SSD.
• The Intel 660p: one of the few QLC NVMe SSDs on the market. The 660p is being replaced by the new 665p, but both are still widely available. Although the 665p is a little faster, the 660p still has no trouble circling SATA drives under the right conditions.

We don’t have any non-Samsung 4TB consumer SSDs to compare; Western Digital Blue is pretty much the only other consumer 4TB SATA SSD, and Rocket and Rocket Q drives based on the Sabrent Phison E12 are the current options on the NVMe side. The rest of the 4+ TB SSD options are business units that lack SLC caching and idle power management and are much more expensive than anything else this review is looking at.

Ultimately, most of the competition against multi-TB SSDs comes from hard drives, the current alternatives for high-capacity drives. Multi-TB hard drives are still much cheaper than multi-TB SSDs, but for many consumers the big question raised by drives like the 870 QVO is whether it is reasonable to still move all of their storage to solid state. That doesn’t necessarily require SSDs to match hard drives on a $ / GB basis, because there are so many advantages to SSDs that it’s worth paying at least a little bit more.

Representing the hard drive market, we have a Western Digital WD Red 4TB, the pre-SMR model WD40EFRX. It is the newest and largest hard drive I have on hand because my home office has been drowning in SSD for years. (A good problem to have).