Over the last week or so, there have been a growing number of reports from owners of M1 Arm-based powered computers that hard drive health reports are showing excessive use of the SSD, which could shorten the lifespan of the computer as the drives are soldered onto the motherboard.

The reports have been seen on Twitter (see below for some examples) as well as elsewhere.

The macOS shows that the internal SSD of these M1 Macs has reported: “extremely high drive writes over a relatively short time.” In an extreme case, one user reports that their SSD has already had consumed about 13% of the maximum warrantable total bytes written.

“Some more professional users of the new M1 Macbooks are experiencing extremely high drive writes over relatively short time.

The most severe cases have "consumed" about 10-13% of the maximum warrantable TBW value of the SSDs (given their capacity & using values for equivalent market-available NVMe drives).”

Even though SSDs are chips rather than mechanical parts, SSDs do have a finite lifespan and that is based on the amount of reading and writing of data they are asked to do.

What this means is that the more you write data to an SSD, the shorter its lifespan will be before it starts to become unreliable and eventually fail.

The problem originates from the way SSDs are designed and work. There is a limit to the number of times each cell used to store data, can only be written to, before it fails. This is because each time a cell is written to, it has to first be erased and then the new data, written. Multiple writes wear down the cells to a point where they don't hold a charge and it is this that causes the drive to fail.

What makes this even more of a problem is that the internal storage of Apple’s M1 Macs is soldered to the logic board, which could mean a significant repair bill for the user, where it could be necessary to replace the logic board or worse, just because the SSD has worn out.

SSDs potential lifespan is often measured by Terabytes Written (TBW), referring to how much data can be written to a drive, as set by the manufacturer before they consider that it could become unusable.

This is usually expected to be In the vast majority of cases, this typically is years or even a decade of use by most users.

Possible Causes

At the time of writing the causes for this excessive wear on M1 Mac’s SSDs is unknown. There are suggestions that it could be because the M1 chip uses the SSD as virtual RAM, which requires a lot of data swapping or it is a bug in macOS Big Sur.

UPDATE: Questions Raised About the Accuracy Of The Data

Since publishing this article, we have learnt that there may be some problems with the data acquired by users, on which they are basing their concerns. For example, AppleInsider has queried the reliability of the data…

“For a start, the lack of decent SMART reporting in macOS itself led users to install tools like Smart Monitoring Tools.

It is likely that if there were better SMART reporting tools available, rather one that required installation and running it from the terminal, there would be a better picture of the current situation.

However, the results from the tool may not necessarily be accurate, due to consistent problems with SMART reporting in general. It also isn't clear if the system on a chip and combined caching on the M1 is causing the SMART reporting tools to display incorrect data.”

It’s not just the Terabytes Written data that they are concerned with. Even something as basic as the “Power On Hours” data published by users is concerning AppleInsider with hours in the order of the low hundreds for a Mac that has been supposed to be running for 2 months. So they ran some tests of their own…

“In AppleInsider testing with its writers using M1 Macs since the issue first cropped up on February 13, the power-on hours statistic showed 300 hours for one, despite being on for 23 hours a day since its initial purchase on the first day of availability. Another writer has owned their Mac mini for two months, and has racked up a mere 70 hours on that figure — about nine work days.

This may indicate that the tool isn't necessarily receiving the correct data in its queries.”

It does now seem that Apple is looking into this issue. An AppleInsider source within Apple corporate, not authorised to speak on behalf of the company, said…

"While we're looking into the reports, know that the SMART data being reported to the third-party utility is incorrect, as it pertains to wear on our SSDs"

However, their source refused to elaborate any further on the matter when pressed for specifics.

Mike looked at his Mac mini 2018 using the SMART Check feature in TechTool Pro 13. The screenshot on the left is Mike’s Angelbird SSD, which you will see appears to the software as if it is an Apple-branded drive.

The screenshot on the right is the Apple SSD built into his Mac mini 2018.

What is interesting to note is that Techtool Pro is only able to get limited SMART Data from the genuine Apple SSD as opposed to much more data from the Angelbird drive, which may be explained by the comment from AppleInsider’s unofficial source.

Are The Tools Up To The Job?

This saga raises the question as to whether the software tools we use to determine the health of our Apple computers are fit for purpose. AppleInsider said…

“The nearest thing macOS has to a tool for this purpose is Disk Utility, but while it is useful for managing disks, it remains terrible for determining drive health. The only element you have within is the SMART status line, which either declares "Verified" or "Failing," with no real gradient, or data in any way presented to the user.

Elements like the Smart Monitoring Tool are difficult for typical Mac users to install and use, but anyone wanting more detail about how their drive is running has to look in that direction. This would be a great chance for Apple to add its own tool, one that correctly reports data about the drive's health given the M1's unique storage implementation.”

Unofficially its good to know that Apple is looking into this but it would be good to have an official confirmation from Apple would go a long way to lay concerns. The other reassuring outcome from this saga would be reliable tools to report the true healthiness of our Mac computers.