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

    What's the purpose of those? I mean I recently bought MP600 1 TB for the price of MP600 Core same capacity. I didn't bought it for it's speed but it's TBW endurance which is by the way twice as MP600 Core 4GB.
    This doesn't have any market place in my opinion when you can buy a drive with same controller and same 96 layer but TCL NAND for a same price or just a little bit more money.
  • SarahKerrigan - Friday, April 9, 2021 - link

    Yeah, right now really the only sweet spot for QLC is at 4TB.
  • powerarmour - Saturday, April 10, 2021 - link

    Absolutely, enough with this anti-consumer QLC junk. There needs to be a better tech solution that doesn't trade performance for density's sake, a better balance would be more ideal.
  • Oxford Guy - Sunday, April 11, 2021 - link

    'that doesn't trade performance for density's sake'

    Performance, value (by harming TLC's economy of scale), and longevity.

    30% density increase for twice as many voltage states is not a great bargain.
  • ballsystemlord - Saturday, April 10, 2021 - link

    A pig with lipstick on is still a pig. QLC is currently a pig.
    It ->still<- has huge leaps and bounds to go for before it becomes a viable SSD storage medium.
  • Oxford Guy - Sunday, April 11, 2021 - link

    There are no leaps and bounds for it.

    The one thing that made TLC good enough was the transition from planar to 3D manufacturing.

    QLC has no such saving grace in store – that's my bet.
  • arashi - Sunday, April 11, 2021 - link

    4D manufacturing /s
  • 0ldman79 - Saturday, April 17, 2021 - link

    With enough channels QLC and 4TB+ drives could work.

    SLC cache, QLC long term storage and 8-16 channels, that could work.

    Honestly for longevity and performance I'm not sure QLC is going to beat out TLC unless they get QLC up to TLC's endurance and speed, which is likely not financially viable even if technically possible.
  • GeoffreyA - Sunday, April 11, 2021 - link

    They're trying to pull the wool over people's eyes and sell margarine at the price of butter, hoping nobody notices.
  • dickeywang - Sunday, April 11, 2021 - link

    Unfortunately, the market isn't driven by consumers who can tell the difference between QLC and TLC. Most of the time, consumers just want to have larger capacity with lower prices. If it is the garbage they want, it is what they get. That's the sad story of capitalism.

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