QLC Goes To 8TB: Samsung 870 QVO and Sabrent Rocket Q 8TB SSDs Reviewed
by Billy Tallis on December 4, 2020 8:00 AM ESTPower Management Features
Real-world client storage workloads leave SSDs idle most of the time, so the active power measurements presented earlier in this review only account for a small part of what determines a drive's suitability for battery-powered use. Especially under light use, the power efficiency of a SSD is determined mostly be how well it can save power when idle.
For many NVMe SSDs, the closely related matter of thermal management can also be important. M.2 SSDs can concentrate a lot of power in a very small space. They may also be used in locations with high ambient temperatures and poor cooling, such as tucked under a GPU on a desktop motherboard, or in a poorly-ventilated notebook.
| Sabrent Rocket Q 8TB NVMe Power and Thermal Management Features |
|||
| Controller | Phison E12S | ||
| Firmware | RKT30Q.2 (ECFM52.2) | ||
| NVMe Version |
Feature | Status | |
| 1.0 | Number of operational (active) power states | 3 | |
| 1.1 | Number of non-operational (idle) power states | 2 | |
| Autonomous Power State Transition (APST) | Supported | ||
| 1.2 | Warning Temperature | 75°C | |
| Critical Temperature | 80°C | ||
| 1.3 | Host Controlled Thermal Management | Supported | |
| Non-Operational Power State Permissive Mode | Supported | ||
The Sabrent Rocket Q claims support for the full range of NVMe power and thermal management features. However, the table of power states includes frighteningly high maximum power draw numbers for the active power states—over 17 W is really pushing it for a M.2 drive. Fortunately, we never measured consumption getting that high. The idle power states look typical, including the promise of quick transitions in and out of idle.
| Sabrent Rocket Q 8TB NVMe Power States |
|||||
| Controller | Phison E12S | ||||
| Firmware | RKT30Q.2 (ECFM52.2) | ||||
| Power State |
Maximum Power |
Active/Idle | Entry Latency |
Exit Latency |
|
| PS 0 | 17.18 W | Active | - | - | |
| PS 1 | 10.58 W | Active | - | - | |
| PS 2 | 7.28 W | Active | - | - | |
| PS 3 | 49 mW | Idle | 2 ms | 2 ms | |
| PS 4 | 1.8 mW | Idle | 25 ms | 25 ms | |
Note that the above tables reflect only the information provided by the drive to the OS. The power and latency numbers are often very conservative estimates, but they are what the OS uses to determine which idle states to use and how long to wait before dropping to a deeper idle state.
Idle Power Measurement
SATA SSDs are tested with SATA link power management disabled to measure their active idle power draw, and with it enabled for the deeper idle power consumption score and the idle wake-up latency test. Our testbed, like any ordinary desktop system, cannot trigger the deepest DevSleep idle state.
Idle power management for NVMe SSDs is far more complicated than for SATA SSDs. NVMe SSDs can support several different idle power states, and through the Autonomous Power State Transition (APST) feature the operating system can set a drive's policy for when to drop down to a lower power state. There is typically a tradeoff in that lower-power states take longer to enter and wake up from, so the choice about what power states to use may differ for desktop and notebooks, and depending on which NVMe driver is in use. Additionally, there are multiple degrees of PCIe link power savings possible through Active State Power Management (APSM).
We report three idle power measurements. Active idle is representative of a typical desktop, where none of the advanced PCIe link power saving features are enabled and the drive is immediately ready to process new commands. Our Desktop Idle number represents what can usually be expected from a desktop system that is configured to enable SATA link power management, PCIe ASPM and NVMe APST, but where the lowest PCIe L1.2 link power states are not available. The Laptop Idle number represents the maximum power savings possible with all the NVMe and PCIe power management features in use—usually the default for a battery-powered system but not always achievable on a desktop even after changing BIOS and OS settings. Since we don't have a way to enable SATA DevSleep on any of our testbeds, SATA drives are omitted from the Laptop Idle charts.
Note: Last year we upgraded our power measurement equipment and switched to measuring idle power on our Coffee Lake desktop, our first SSD testbed to have fully-functional PCIe power management. The below measurements are not a perfect match for the older measurements in our reviews from before that switch.
The Samsung 870 QVO SSDs have lower active idle power consumption than the NVMe competition, though our measurements of the 4TB model did catch it while it was still doing some background work. With SATA link power management enabled the 8TB 870 QVO draws more power than the smaller models, but is still very reasonable.
The Sabrent Rocket Q's idle power numbers are all decent but not surprising. The desktop idle power draw is significantly higher than the 49mW the drive claims for power state 3, but it's still only at 87mW which is not a problem.
The Samsung 870 QVO takes 1ms to wake up from sleep. The Sabrent Rocket Q has almost no measurable wake-up latency from the intermediate desktop idle state, but takes a remarkably long 108ms to wake up from the deepest sleep state. This is one of the slowest wake-up times we've measured from a NVMe drive and considerably worse than the 25ms latency the drive itself promises to the OS.
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Scour - Monday, December 7, 2020 - link
After experiences which some QLC-SSDs from Samsung and Crucial I have to say: Stay away from QLC if you want performance.Maybe it´s OK for ppl who install a windows and store some music or photos on it, but if you want to write larger amount of data you will be faster with HDDs.
It´s a shame that some ppl recommend a QVO because it have a Samsung-controller and DRAM. Don´t agree with them because some cheap TLC-SSDs are much faster.
Oxford Guy - Monday, December 7, 2020 - link
Samsung is often overrated anyway. Their planar TLC drives were so poorly made that they have to periodically rewrite the data that's on the drive to maintain decent performance.I also remember the company's completely bogus power consumption claims, claims that were taken as truth by consumers who would recommend the drives based on the deception.
Scour - Tuesday, December 8, 2020 - link
My 840 (first version) never was good, it was slower than some of my cheapest SSDs in daily use. I use it now for video-recording on a set-top-box. It´s fast enough for the writing-speed and it gets erased all 2-3 weeks.But the 850 and 860 Evo works good and fast.
The QVO-series maybe beats other QLC-products like DRAM-less BX500 (so far never seen benchmarks of new Sandisk Plus with QLC) but is to expensive in capacities less than 8TB
WaltC - Monday, December 7, 2020 - link
This has to be the first NMEe .M2-interface vs. SATA3-interface SSD comparison that ignores the differences in bus connections as if they don't exist--or as if they don't matter. Scratching my head over this one. Max optimal bandwidth for Sata3 SSD's is generally less than 550MB/s. Max optimal bandwidth for an .M2 NVMe 3x4 PCIe 3 drive like the Sabrent here is 3.5-5.x GB/s. And for PCIe 4 3x4 NVMe drives like the 980 Pro from Samsung, the max optimal bandwidth is as much a 7+ GB/s. Comparing the internal drive controllers and the onboard ram between SSD's is fine and should be done--but *never* at the expense of treating the drive interfaces into the system as if they just don't matter, imo...;) If people are merely looking capacities and prices without regard to performance this might be a helpful review. But when is that ever really the case? With SATA3 SSDs, it doesn't really matter about the internals, the performance is caped at < 550MB/s. The bottleneck being the drive's system interface.peevee - Wednesday, December 9, 2020 - link
2TB of SLC is equal to 8TB of QLC. I doubt the SLC flash is separate from QLC, they probably use QLC in SLC mode until 2TB fill up, and then start compressing the data into QLC. So the switch might happen without constant sequential write too.ballsystemlord - Wednesday, December 9, 2020 - link
@Billy , Under "Random Write Performance" (burst and sustained,) you'll notice that you wrote the same comment twice by mistake.zhpenn - Monday, February 8, 2021 - link
About the 8TB version power consumption, I notice in the spec is 5.5W when compare to 860 EVO(4W) Can I put 870 QVO 8TB into a USB 3.0 SATA enclosure and used it without an unstable issue? or it may eject unexpectedly or slow speed due to high power consumption?PushT - Thursday, October 14, 2021 - link
How big is the cache on this drive ? The 32 GB "sustained"transfer falls within that cache, is that right ? Say I wanted to make a backup of my whole system, on this drive, or just move the backup to it, or other large files for that matter. How would the sustained 128KB write performance look ? Why do you test for this rather small transfer size when it only showcases the faster cache ? Am I wrong ? Please tell me why you can't just as well include longer and larger transfers, so as to show what happens when the QLC nand is written to ?PushT - Thursday, October 14, 2021 - link
To be fair this drive has a large dynamic cache. You can transfer a lot of data before you hit the QLC nand directly. But if you look at the review at Tom's you can see how the perfomance actually drops to 200 MB/s after the cache is filled up, about that of a WD black HDD. That is not too impressive. Also I wonder about the heat when you start using these small drives for bulk storage...PushT - Thursday, October 14, 2021 - link
With the Samsung 870 Evo, as an example, you can fill up the whole drive with sequential writes at 500 MB/s. Looking at a potential bulk storage solution, you would write a full hypothetical 8TB Samsung Evo 870 sata ssd in approximately 4,43 hours, whereas filling a Sabrent rocket 8TB would take about 6,2 hours. So depending on your usage, there are trade-offs. If I was to copy drives I don't see why I would use this over a top Sata ssd.