Question Crystal Diskinfo doesn't report SSD writes

Sep 7, 2021
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I bought a secondhand SSD. I run the disk info to see the lifetime of the SSD and to check if I was fooled with the used SSD-drive purchase, however, despite it reads "good", I can't get any writes visible. How is that?

But in the attribute details below, what is "Total LBAs written" and then some mystical HEX value?

See the screenshot below:

 
The total number of bytes written is less than 1GB (144MB), if the units are interpreted as sectors.

https://ipv4.google.com/search?q=0x45153+x+512+bytes+in+MB

The SSD has recorded an average wear levelling count of 19 (= 0x13 in hexadecimal), so this means that the total writes to NAND amount to 256GiB x 19 = 5.2TB. The actual number of host writes would depend on the write amplification.

I would write a 1GiB file to the SSD and then compare attribute F1 before and after. I suspect that each unit may correspond to 16MiB rather than a single sector (512 bytes).

BTW, you can use Google's calculator to convert the "mystical" hexadecimal values to decimal.

https://ipv4.google.com/search?q=0x45153+in+decimal

I don't see any super capacitor in any online images, so I'm wondering whether attribute C9 has been misinterpreted.
 
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Sep 7, 2021
5
0
10
0
The total number of bytes written is less than 1GB (144MB), if the units are interpreted as sectors.

https://ipv4.google.com/search?q=0x45153+x+512+bytes+in+MB

The SSD has recorded an average wear levelling count of 19 (= 0x13 in hexadecimal), so this means that the total writes to NAND amount to 256GiB x 19 = 5.2TB. The actual number of host writes would depend on the write amplification.

I would write a 1GiB file to the SSD and then compare attribute F1 before and after. I suspect that each unit may correspond to 16MiB rather than a single sector (512 bytes).

BTW, you can use Google's calculator to convert the "mystical" hexadecimal values to decimal.

https://ipv4.google.com/search?q=0x45153+in+decimal

I don't see any super capacitor in any online images, so I'm wondering whether attribute C9 has been misinterpreted.
The total writes is definitely more than 1GB, I have a fresh Win10 installation + programs on it, plus what ever the previous owner had done.

So, do I understand correctly. You convert the hex number to decimal, which would be 282963 according to google's calculator. And this number is most likely a multiply of something.

Anyway, the wear leveling 0x13 is 19 in dec, and from this you deduced that the whole storage capacity (256GB) is written 19 times. Well... that is not much, so I think I will have lots of lifetime left with this SSD.

Would be nice if those softwares reported the writes clearly in GB, just like they do for all other SSD. What is wrong with this model?
 
Sep 7, 2021
5
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10
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I would write a 1GiB file to the SSD and then compare attribute F1 before and after. I suspect that each unit may correspond to 16MiB rather than a single sector (512 bytes).
I wrote some data, I estimated ~40-50GB. The F1 increased from 282963 to 286100. This is a difference of 3137.
Multiplying this with 16MB would make 50192MB, so quite close to the estimated written amount.

Thanks for clarifying this, however, what is 16MB, where does it come from?
 
16MB was the closest "binary" capacity which I was able fit to your data. It's 2 to the power of 24. The nearest alternatives were 8MB or 32MB.

It appears that Samsung is counting the number of 16MB blocks written to the drive rather than the number of 512-byte sectors. You and I are now aware of this, but CrystalDiskInfo is not. :)

BTW, SMART is not standardised, so manufacturers are free to interpret the SMART attributes any way they choose. That's why CrystalDiskInfo, and even Samsung Magician, get it wrong sometimes.
 
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