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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heffeque - Friday, December 4, 2020 - link
"Of course we hope that firmwares don't have such bugs, but how would we know unless someone looked at the numbers?"Well on a traditional HDD you also have to hope that they put Helium in it and not Mustard gas by mistake. It "can" happen, but how would we know if nobody opens every single HDD drive?
In a serious note, if a drive has such a serious firmware bug, rest assured that someone will notice, that it will go public quite fast and that it will end up getting fixed (like it has in the past).
Spunjji - Monday, December 7, 2020 - link
Thanks for responding to that "how do you know unless you look" post appropriately. That kind of woolly thinking really gets my goat.joesiv - Monday, December 7, 2020 - link
Well, I for one would rather not be the one that discovers the bug, and lose my data.I didn't experience this one, but it's an example of a firmware bug:
https://www.engadget.com/2020-03-25-hpe-ssd-bricke...
Where I work, I'm involved in SSD evaluation. A drive we used in the field had a nasty firmware bug, that took out dozens of our SSD's after a couple years of operation (that was well within their specs), The manufacturer fixed it in a firmware update, but not until a year + after release, so we shipped hundreds of product.
Knowing that, I evaluate them now. But for my personal use, where my needs are different, I'd love it if at least a very simple check was done in the reviews. It's not that hard, review the SSD, then check to see if the writes to NAND is reasonable given the workload you gave it. It's right there in the smart data, it'll be in block sizes, so you might have to multiply it by the block size, but it'll tell you a lot.
Just by doing something similar, we were able to vet a drive that was writing 100x more to NAND than it should have been, essentially it was using up it's life expectancy 1% per day! Working with the manufacturer, they eventually decided we should just move to another product, they weren't much into firmware fixes.
Anyways, someone should keep the manufactuers honest, why not start with the reviews?
Also, no offence, but what is the "wolly thinking" are you talking about? I'm just trying to protect my investment and data.
heffeque - Tuesday, December 8, 2020 - link
As if HDD didn't have their share of problems, both firmware and HW (especially the HW). I've seen loads of HDD die in the first 48 hours, then a huge percentage of them no later than a year afterwards.My experience is that SDD last A LOT longer and are A LOT more reliable than HDD.
While HDD had been braking every 1-3 years (and changing them was a high cost due to the remote location, and the high wages of Scandinavian countries), when we changed to SSD we had literally ZERO replacements to perform since then so... can't say that the experience with hundreds of SSD not failing vs hundreds of HDD that barely last a few years goes in favor of HDD in any kind of measure.
In the end, paying to send to those countries a slightly more expensive device (the SSD) has payed for itself several-fold in just a couple of years.
MDD1963 - Friday, December 4, 2020 - link
I've only averaged .8 TB per *month* over 3.5 years....joesiv - Monday, December 7, 2020 - link
Out of curiousity, how did you come to this number?Just be aware that SMART data will track different things. You're probably right, but SMART data is manufactuer and model dependant, and sometimes they'll use the attributes differently. You really have to look up the smart documentation for your drive, to be sure they are calculating and using the attributes the way your smart data utility is labeling them as. Some manfacturers also don't track writes to NAND.
I would look at:
"writes to nand" or "lifetime writes to flash" - which for some kingston drives is attribute 233
"SSD Life Left" - which for some ADATA drives is 232 (ADATA), and Micron/Crucial might be is 202), this is actually usually calculated based on average block erase count against the rated block erase counts the NAND is rated for (3000ish for MLC, much less for 3d nand)
A lot of maufactuers haven't included the actual NAND writes in their SMART data, so it'd be hard to get to, and should be called out for it (Delkin, Crucial).
"Total host writes" is what the OS wrote, and what most viewers assume is what manufactuers are stating when they're talking about drive writes per day or TB a day. That's the amount of data that is fed to the SSD, not what is actually written to NAND.
Also realize that wear leveling routines can eat up SSD life as well. I'm not sure how SLC mode that newer firmwars have affects life expectancy/nand writes actually.
stanleyipkiss - Friday, December 4, 2020 - link
Honestly, if the prices of these QLC high-capacity drives would drop a bit, I would be all over them -- especially for NAS use. I just want to move away from spinning mechanical drives but when I can get a 18 TB drive at the same price of a 4-8 TB SSD, I will choose the larger drive.Just make them cheaper.
Also: I would love HIGHER capacity, and I WOULD pay for it... Micron had some drives and I'm sure some mainstream drives could be made available -- if you can squeeze 8TB onto M.2 then you could certainly put 16TB on a 2.5 inch drive.
DigitalFreak - Monday, December 7, 2020 - link
Ask and ye shall receive.https://www.pcgamer.com/sabrent-is-close-to-launch...
Xex360 - Friday, December 4, 2020 - link
The prices don't make any sense, you can get multiple drives for the same capacity but less money and more performance and reliability, and should cost more because they use more material.inighthawki - Friday, December 4, 2020 - link
At least for the sabrent drive, M.2 slots can be at a premium, so it makes perfect sense for a single drive to cost more than two smaller ones. On many systems being able to hook up that many drives would require a PCIe expansion card, and if you're not just bifurcating an existing 8x or 16x lane you would need a PCIe switch which is going to cost you hundreds of dollars at minimum.