Conclusion

The Sabrent Rocket Q4, Corsair MP600 CORE and related drives form the first crop of QLC drives to support PCIe Gen4. It is clear from our testing that the PCIe Gen4 support doesn't automatically make these drives high-end. The Gen4 capability on these drives isn't a big deal for overall performance, though they are incrementally faster than most PCIe Gen3 QLC drives.

The Rocket Q4 and MP600 CORE definitely provide faster sequential transfer speeds than other QLC drives and entry-level TLC drives, but for random IO the Intel SSD 670p often steals the spotlight despite only supporting PCIe gen3 on its host interface. Optimizing for fast sequential IO is a great way to produce big numbers for marketing purposes, but the tradeoffs made by the Intel 670p seem for the most part to better for the real world.

These Gen4 QLC drives inherit the most notable problem with the Phison E16 controller - the high power consumption- and this adds on to the poor efficiency of QLC NAND. The combination still isn't particularly prone to overheating or thermal throttling during normal consumer use, but heatsinks do make more sense for these drives than on most M.2 SSDs currently shipping with fancy heatsinks. There's not much demand yet for PCIe Gen4 SSDs for notebooks, but these drives are definitely ill-suited to that role.

Previous QLC NVMe drives had already proven that QLC can be an acceptable route to mainstream NVMe performance, provided that the drive has a high enough capacity. The Rocket Q4 and MP600 CORE show that peak performance can be extended even further, but they don't do much to illustrate how worst-case performance can be improved to further reduce the downsides of QLC.

NVMe SSD Price Comparison
April 9, 2021
  500 GB 1 TB 2 TB 4 TB
Sabrent Rocket Q4
PCIe Gen4, QLC
  $149.98
(15¢/GB)
$279.98
(14¢/GB)
$689.98
(17¢/GB)
Corsair MP600 CORE
PCIe Gen4, QLC
  $154.99
(15¢/GB)
$309.99
(15¢/GB)
$644.99
(16¢/GB)
Mushkin DELTA
PCIe Gen4, QLC
  $159.99
(16¢/GB)
$299.99
(15¢/GB)
$599.99
(15¢/GB)
Sabrent Rocket Q
QLC
$64.99
(13¢/GB)
$109.98
(11¢/GB)
$219.98
(11¢/GB)
$599.98
(15¢/GB)
Corsair MP400
QLC
  $109.99
(11¢/GB)
$229.99
(11¢/GB)
$593.99
(15¢/GB)
Mushkin ALPHA
QLC
      $569.99
(14¢/GB)
Intel SSD 670p
QLC
$69.99
(14¢/GB)
$114.99
(11¢/GB)
$249.99
(12¢/GB)
 
Samsung SSD 980
DRAMless, TLC
$69.99
(14¢/GB)
$129.99
(13¢/GB)
   
WD Blue SN550
DRAMless, TLC
$59.99
(12¢/GB)
$109.99
(11¢/GB)
   
SK hynix Gold P31
TLC
$74.99
(15¢/GB)
$134.99
(13¢/GB)
   
WD Black SN750
TLC
$69.99
(14¢/GB)
$139.99
(14¢/GB)
$299.99
(15¢/GB)
$799.99
(20¢/GB)

As we saw with the TLC drives when the Phison E16 controller first brought PCIe 4 support to consumer SSDs, that extra bandwidth comes at a significant premium. For the more mainstream capacities, the E16 QLC drives are substantially more expensive than the PCIe Gen3 QLC drives using the older E12 controller, or even the recent Intel SSD 670p. However, at 4TB, the premium for Gen4 on a QLC drive is a lot smaller. Mainstream PCIe Gen3 TLC drives are also cheaper than the Gen4 QLC drives, for capacities below 4TB. At and above 4TB there really aren't many options, and almost all of the are QLC-based. It is disappointing that upgrading to PCIe Gen4 has so far precluded these Phison drives from offering the 8TB capacity that is available from Phison E12 drives. That will likely come as 28nm controllers make way for newer models on 12nm or smaller.

These Gen4 QLC SSDs are not a great general-purpose storage solution; they certainly don't combine PCIe Gen4 and QLC and come out with only the best advantages of each. But they are still suitable for some use cases, especially centered around higher capacities.

 
Mixed IO Performance and Idle Power Management
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  • ZolaIII - Friday, April 9, 2021 - link

    Actually 5.6 years but compared to same MP600 TLC 8x that much or 44.8 years and for just a little more money. But seriously buying a 1 TB mp600 which will be enough regarding capacity and which will last 22.4 years under same explanation (vs 2.8 for Core) then that makes a hell of a difference.
  • WaltC - Saturday, April 10, 2021 - link

    In far less than 22 years your entire system will have been replaced...;) IE, for the use-life of the drive you will never wear it out. The importance some people place on "endurance" is really weird. I have a 960 EVO NVMe with endurance estimates of 75TB: the drive is three years old this month and served as my boot drive for two of those three years, and I've used 19.6TB of write as of today. Rounding off, I have 55TB of write endurance remaining. That makes for an average of 6.5 TBs written per year--but the drive is no longer my boot/Win10-build install drive, so an average of 5TBs per year as strictly a data drive is probably overestimating, but just for fun, let's call it 5 TBs write per year. That means I have *at least* 11 years of write endurance remaining for this drive--which would mean the drive would have lasted at least 14 years in daily use before wearing out. Anyone think that 11 years from now I'll still be using that drive on a daily basis? I don't...;) The fact is that people worry needlessly about write endurance unless they are using these drives in some kind of mega heavy-use commercial setting. Write endurance estimates of 20-30 years are absurd and when choosing a drive for your personal system such estimates should be ignored as they have no meaning--they will be obsolete long before they wear out. So, buy the drive performance at the price you want to pay and don't worry about write endurance as even 75TB is plenty for personal systems.
  • GeoffreyA - Sunday, April 11, 2021 - link

    It would be interesting to put today's drives to an endurance experiment and see if their actual and advertised ratings square.
  • ZolaIII - Sunday, April 11, 2021 - link

    I have 2 TB writes per month, using PC for productivity, gaming and transcoding and still not to much. If I used it professionally for video that number would be much higher (high bandwidth mastering codes). To hell transcoding a single Blu-ray movie quickly (with GPU for sakes of making it HLG10+) will eat up to 150GB of writes and that's not a rocket science task to perform. By the way its not that PCIe interface will go anywhere and you can mont old NVMe to a new machine.
  • Oxford Guy - Sunday, April 11, 2021 - link

    One can't choose performance with QLC. It's inherently slower.

    It's also inherently reduced in longevity.

    Remember, it has twice as many voltage states (causing a much bigger issue with drift) for just a 30% density increase.

    That's diminished returns.
  • haukionkannel - Friday, April 9, 2021 - link

    Well, soon QLS can be seen only in highend top models, when middle range and low end go to PLS or what ever...
    for SSD manufacturers it makes a lot of Sense because they save money in that way. Profit!
  • nandnandnand - Saturday, April 10, 2021 - link

    5/6/8 bits per cell might be ok if NAND manufacturers found some magic sauce to increase endurance. There was research to that effect going on a decade ago: https://ieeexplore.ieee.org/abstract/document/6479...

    TLC is not going away just yet, and they can just increase drive capacities to make it unlikely an average user will hit the limits.
  • Samus - Sunday, April 11, 2021 - link

    When you consider how well perfected TLC is now that it has gone full 3D and the SLC cache + overprovisioning eliminate most of the performance\endurance issues, it makes you wonder if MLC will ever come back. It's almost completely disappeared even in enterprise.
  • Oxford Guy - Sunday, April 11, 2021 - link

    3D manufacturing killed MLC. It made TLC viable.

    There is no such magic bullet for QLC.
  • FunBunny2 - Sunday, April 11, 2021 - link

    "There is no such magic bullet for QLC."

    well... the same bullet, ver. 2, might work. that would require two steps:
    - moving 'back' to an even larger node, assuming that there's sufficient machinery at such node available at scale
    - getting two or three times the layers as TLC currently uses

    I've no idea whether either is feasible, but willing to bet both gonads that both, at least, are required.

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