understanding total writes values on SSD

Good day.

Crystal Disk Info shows values for Total Host Writes and Total NAND Writes on an SSD. I was wondering if the lower of those two values is a subset of the other value. Thank you for your attention.

Hi,

The difference between them is caused by write amplification.

https://www.raxco.nl/pdf/SSDPerformance.pdf

Good day. Just resurrecting my old thread.

CrystalDiskInfo shows the following values for my Kingston A400 SSD:

Health Status: 91%
Total Host Reads: 10276 GB
Total Host Writes: 6123 GB
Total NAND Writes: 5925 GB
Power On Hours: 2199 hours

Assuming these values are accurate, I was wondering if someone could answer the following two (ok, three) questions.

1. Isn't the number of NAND writes supposed to be higher than the number of total host writes? Does the fact that it isn't mean that there may be a problem?

2. For a 2199-hour usage, is the health value a concern?

Thank you for your attention.

This crucial 525gb mx300 is allegedly rated at 160tb. The controller is reporting double that. Perhaps crucial deliberately understated the endurance.

8.98tb written and it reports 98%. I expect it to change to 97% at about 9.6tb written

justtesting,

SIW2 is correct - the main thing here is the overall health status which shows 91% of life remaining.

I'm not certain why the total NAND writes would be lower than the host writes, that seems odd to me. However, I would suspect that the more important, and more accurate number would be the total NAND writes because that comes directly from the SSD controller.

You asked if the health value is a concern for a 2,199-hour usage. That question cannot really be answered simply because the number of hours usage for an SSD is pretty much irrelevant.

Let's take an example: Suppose you install an SSD in your system, but you never use it. It's powered on for 10,000 hours but you never write to it. Its health status should still be shown as 100% because the health status is mainly a measure of how much data has been written to the drive vs the rated endurance.

So, let's take some random numbers here as an example for overall health. Let's say that you have had that SSD for 2 years and you still have 91% life remaining. If you write data at a constant rate, a current health rating of 91% indicates that you go another ten times that long or about 20 years more before the drive reaches its endurance rating. Of course, if you start writing a lot more data to the drive than you have in the past, then that time would be reduced. Likewise, write less data and that time will be increased.

Going off on a little bit of a tangent here, but I'll assume that you have the 480GB drive since I don't know for sure which capacity drive you have. What we know about that model and capacity drive is that it has an endurance rating of 160TB written and a 3-year warranty. That means that you could write roughly 146GB every single day to that drive during the 3-year warranty before you exceed the rated endurance spec. If you have the 960GB model, then that doubles to approximately 292GB every day.

Some final notes: Power on time is more important to a fixed HDD because it has moving parts like bearings, a motor, etc. that wear over time. Also, out of curiosity, is the version of CrystalDiskInfo that you are using current? If not, I would suggest upgrading to see if the values presented still show the same thing. You may also want to run another app such as Hard Disk Sentinel Pro to see if the values reported are in agreement.

Thank you for your quick responses.

Indeed, I am using Crystal Disk Info's latest version, 8.17.5.
And congratulations, you guessed my SSD's capacity is 480 GB. May I suggest you choose your lotto numbers today.

However, thinking arithmetically about the 160 TBW and the 91% remaining life, which may not be the right way of thinking in this matter, if 9% of the SSD's life is gone having written around 6 TB, a simple calculation shows that the disk will reach 0% of remaining life when around 66 TB have been written. Please do not hesitate to show me that this simple reasoning is inaccurate. Thank you for your interest.

That is not very encouraging. Have you tried the manufacturers software to check the health?

SSD Manager - Kingston Technology

You might also try another app such as Hard Disk Sentinel Pro (Hard Disk Sentinel - HDD health and temperature monitoring). If just installing temporarily, you might try the portable edition of the program. I would be curious to see if it aggress.

In the meantime, I'll have to do the math on my SSDs to see if it matches the TBW ratings.