QLC Goes To 8TB: Samsung 870 QVO and Sabrent Rocket Q 8TB SSDs Reviewed
by Billy Tallis on December 4, 2020 8:00 AM ESTMixed Random Performance
Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.
The 8TB Sabrent Rocket Q's performance on the mixed random IO test is much better than any of the other low-end NVMe drives; the DRAMless TLC drives are the slowest in this bunch, and the Intel 660p with its four-channel controller cannot keep up with the Rocket Q's 8-channel Phison E12. The 8TB Samsung 870 QVO is slower than most of the other SATA drives in this bunch, but still has a clear advantage over the 1TB model.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The high-end consumer NVMe drives and the Samsung 860 EVO TLC SATA drive top the power efficiency chart for the mixed random IO test. The Sabrent Rocket Q's efficiency is a significant step down from there, but still a bit better than any of the other low-end drives. The 8TB 870 QVO's efficiency score is worse than the 4TB model's, but clearly better than the 1TB model or either of the DRAMless TLC NVMe drives.
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Both of the 8TB QLC drives show fairly typical performance curves for the mixed random IO test: little or no performance drop when writes are first added to the mix, and then increasing performance that accelerates toward the end of the test as write caching becomes more effective. The 8TB 870 QVO doesn't show the signs of a filled SLC cache that we see from the 1TB model, and neither 8TB QLC drive shows the nearly-flat performance exhibited by the two DRAMless TLC drives.
Mixed Sequential Performance
Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.
The Sabrent Rocket Q's performance on the mixed sequential IO test is competitive with the high-end consumer TLC drives, and far better than the other low-end NVMe options. The 8TB Samsung 870 QVO has distinctly lower performance than the smaller capacities, but isn't quite the worst overall performer.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The good performance of the Rocket Q on the mixed sequential IO test comes at the cost of worse power efficiency than the DRAMless TLC competition, but its efficiency scores are still decent. The 8TB 870 QVO's efficiency scores are worse than any of the other consumer SSDs in this bunch.
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As with several other synthetic tests in our suite, the mixed sequential IO test has the Sabrent Rocket Q showing rather variable performance, though fortunately without any severe drops. It performs a bit better during the more write-heavy half of the test.
The Samsung 870 QVO shows relatively flat and consistent performance throughout this test, but as is common for Samsung drives there's a bit of a decreasing performance trend during the read-heavy half of the test.
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TheinsanegamerN - Monday, December 7, 2020 - link
"50% of people know what QLC means? Is that a joke? 50% of ATers don't understand what that means"Care to back up your staement with evidence? AT is mostly perused by techie people who understand the difference between SLC, MLC, TLC, and QLC.
at_clucks - Wednesday, December 9, 2020 - link
@TheinsanegamerN, yeah, you're swimming in the evidence. Check out the comment section carefully and you'll see how well the average ATer understands this. Some may know something about "bits per cell, whatever that means", some may know it's less reliable because "it wears out faster whatever that means", so they know the marketing concepts but not what lies underneath them. Most will blindly assume SLC > MLC > TLC > QLC not why or how, not what the cell is, how it works, how many levels of charge it can have, how it's read or how it's written, how they're organized, not the impact of the implementation, controller, firmware, OS, not why exactly wear is a thing, not why writes wear the cell but reads aren't an issue, not what planar/2D vs. 3D means, etc. Being a "techie" today means you *buy* a lot of tech and gloss over some articles with bar charts of which product is faster. That's it.If you want me to give "evidence" of every statement I make prepare to provide answers that have enough references in the footnote to look like a PhD thesis.
In the meantime it's all but guaranteed that a regular consumer has no clue what QLC means or that the product name is a reference to QLC. They see an SSD that fits their computer, has a certain capacity, and costs a certain price. Maybe the manufacturer on the label alleviates their concerns.
Knowing QLC has less endurance than SLC ("wears out") or that this is slower than that doesn't mean you understand the tech more than knowing some cars drive faster than others or have lower safety ratings makes you a piston head or mechanic.
ripbeefbone - Friday, December 11, 2020 - link
you're way too onlineOxford Guy - Sunday, December 6, 2020 - link
In large part because product pushers like slickdeals don't list the type of NAND in the listing title.This is the opposite of how manufacturers wanted to use LED to push TV sales so LED was always listed in product listings.
People become aware of what manufacturers want them to become aware of. That's why we have so many marketing programs generating graduates all over the world.
Samus - Sunday, December 6, 2020 - link
Fortunately we know, and we know to stay away from this crap at this price. An 8TB 870 EVO is "worth" $600 to me and that's all I'm willing to pay for a drive that should logically cost much less than 8x1TB SSD's, not the SAME EXACT PRICE at 8x1TB SSD's (the 870 QVO 1TB regularly sells for $80-$90, and is currently $90 at Best Buy.Using Samsung's metric to scale, an 8TB hard drive should cost $400. The controller, DRAM and overall package are the same between drives. The only difference is platters\NAND.
Oxford Guy - Tuesday, December 8, 2020 - link
We knowing is irrelevant because consumer ignorance working in manufacturers’ favor is about the bulk of consumer demand not a small number of people who make extra effort to learn specs manufacturers don’t want us to know about and therefore choose to not push.Oxford Guy - Sunday, December 6, 2020 - link
"Every one of those deals has people saying no to QLC."Apples and oranges. The listing titles don't list the type of NAND.
Oxford Guy - Sunday, December 6, 2020 - link
There is also the trick of them calling TLC and QLC "MLC". Technically, it is multi-layer NAND so they can get away with it, even though it is completely shady.shabby - Sunday, December 6, 2020 - link
First company to do that will be stoned to death.Samus - Monday, December 7, 2020 - link
Do you really think the 860 EVO is MLC like it is advertised as? No, “3-bit” VNAND or more commonly known as TLC. Samsung has been calling TLC [MLC] for years and has it been stoned to death yet.