There are SSDs that lose data when the power is cut off, such as a power outage, and SSDs that do not.

Russ Bishop , a programmer at Apple, reports that 'testing four NVMe SSDs from different brands revealed that some data was deleted when the power was turned off and some did not.'

SSD cache issue – despite flushing, there is a risk of data loss in the event of a power outage
https://www.techgamingreport.com/ssd-cache-issue-despite-flushing-there-is-a-risk-of-data-loss-in-the-event-of-a-power-outage/

Bishop says he randomly selected and tested four NVMe SSDs from four vendors. The content of the test is a simulation of power off to the computer, which is to confirm that the SSD has downloaded the data and then manually disconnect the cable. As a result of this test, it seems that the data on the two SSDs disappeared even though the data should have been stored in the non-volatile NAND flash memory when the power was turned off. Since flash memory is a 'non-volatile semiconductor memory that stores data even when the power is turned off,' Bishop points out that it is strange that data disappears.

Fun story: I tested a random selection of four NVMe SSDs from four vendors. Half lose FLUSH'd data on power loss. That is the flush went to the drive, confirmed, success reported all the way back to userspace. Then I manually yanked the cable. Boom, data gone.

— Russ Bishop (@ xenadu02) February 21, 2022

According to Bishop's test, the cache data of two SSDs has disappeared. On the other hand, the data of the other two did not disappear no matter when the power was turned off.

When Bishop conducted an experiment to turn off the power completely randomly, it seems that one of the four SSDs has a 40% chance of losing data. On the other hand, Bishop said that the data on the two SSDs did not disappear no matter what. Since such verification has not been done on any review site, 'general consumers will assume that it is a computer's specification that data disappears from storage due to a PC crash or power outage,' Bishop said. It is written.

I guess review sites don't test this stuff. Everyone just assumes data disappearing on crash / power loss is just how computers work?

I feel bad for the other two vendors who must have test suites and spent engineering hours making sure FLUSH works, only to find out no one cares

— Russ Bishop (@ xenadu02) February 21, 2022

Normally, the data is temporarily cached for a short period of time, and then the data is stored in the persistent memory (PMEM) portion. The data in the cache disappears in the event of a power outage because some SSDs use volatile memory for the DRAM cache.

In Bishop's test, two SSDs, ' Samsung 970 EVO Plus 2TB ' and ' WD Red SN700 1TB ', did not lose data even when the power was suddenly turned off. Initially, Bishop said about SSD makers whose data disappears when the power is turned off, 'Please forgive the information disclosure because the SSD of that brand will be worthless if you reveal the name.' , I changed my policy and revealed that ' SK Hynix Gold P31 2TB SHGP31-2000GM-2 ' and 'FW 31060C20 Sabrent Rocket 512' had some data deleted due to power failure.

Correction: “Plus” not “Pro”. Exact model and date codes:

Samsung 970 Evo Plus: MZ-V7S2T0, 2021.10
WD Red: WDS100T1R0C-68BDK0, 04Sept2021

— Russ Bishop (@ xenadu02) February 21, 2022

In addition, Bishop says, 'We plan to verify eight more SSDs,' and the following eight SSDs will be verified.

Tomorrow I'll have results for:
Intel 670p
Samsung 980
WD Black SN750
WD Green SN350
Kingston NV1
Seagate Firecuda 530
Crucial P2
Crucial P5 Plus

— Russ Bishop (@ xenadu02) February 23, 2022