How do you calculate it?
The most popular question in our technical support is “Why is the health of my drive 80%?” In other words, “How do you calculate the drive health?”
And the second most popular question is “Where does the estimated lifetime come from?” “Why does it say that the lifetime is not calculated yet?” Here you will find answers to these questions.
Brief and simple
1. We do not calculate the percentage of the drive health. The SSD itself calculates it and gives it to us. Or in other words, this data comes from the manufacturer of the drive.
2. The estimated lifetime is calculated depending on the amount of data written to the drive. If it is not calculated yet, it means that little data has been written to it. Simply wait a bit, it does not usually take more than a week (or two) after the first launch of the program.
More details for those willing to sort it out or for technical specialists.
The S.M.A.R.T. system built into all modern hard drives has been known since the times of hard disk drives. It keeps monitoring various parameters of the drive technical condition and gives it in relative numbers. As soon as the values of the parameters get below the critical level, the drive is considered unreliable and the manufacturer recommends replacing it. However, in practice the drive may continue to function normally and manufacturers themselves say that SMART is rather a recommendation than an exact prediction.
Unlike the case with hard disk drives, everything is more certain in the world of SSDs. The lifetime of flash memory, on which SSDs are based, is limited to 10 000 times of writing (simply speaking). All drives contain firmware making sure that all memory cells are used evenly and monitors how many times data is written to them and how much time there is left for the SSD. Finally, it is this data that the drive firmware summarizes in one of the S.M.A.R.T. parameters called SSD Life Left or Media wear out indicator – and it is this parameter that SSDLife shows in a convenient and understandable way.
Of course, the first question you ask is what will happen when the drive is worn out 100% (the health is 0%). See the answer to this question at the end of this page.
So, we know the exact lifetime capacity of an SSD and can monitor changes in it. However, most of the drives also show data about written and/or read information in their S.M.A.R.T. parameters.
Note: by the way, some manufacturers give the total amount of data written to the drive as one of the drive lifetime indicators. For example, Intel guarantees that the total of about 37 TB of data will be written to X25-M drives (20 GB per day for 5 years: “The drive will have a minimum of 5 years of useful life under typical client workloads with up to 20 GB host writes per day.”).
Why is it impossible to calculate the date at once?
It's a simple mathematical problem: in order to calculate it at once, we need to know at least the date when you wrote data to the drive the first time, but unfortunately, drives do not provide this information. That is why we need some time after the first launch of SSDLife to monitor how intensively you use your SSD in order to determine its average load. And as soon as we can calculate the approximate average amount of data written to the drive per day, we will be able to determine the time it will take you to use the entire lifetime capacity of the drive, which means we will be able to calculate the date when the lifetime of the SSD will be over. Of course, this date will keep changing depending on how the intensity of the drive usage changes.
Why does the date change dramatically?
In some cases, the estimated lifetime can change dramatically. It happens if the amount of data written to the drive quickly increases. For example, if you install some large game. But do not worry, literally in a couple of days SSDLife will figure out that it was a one-time upsurge and the disk is back to its normal amounts of written data so it will correct the estimated lifetime.