Question I think Crystal Disk Info giving inaccurate information ?

[universalrule]

I just checked 2 of my portable SSDs. Both of their TBW is 600. One is WD Blue SSD 3D and another one is Sandisk Ultra SSD 3D. The Crystal Disk Info shows me something very wrong.

https://imgur.com/7Ml6LdF

https://imgur.com/CfRzKFK

As you can see above, WD has written more than Sandisk, but the lifespan still 99% remains whereas Sandisk indicates 98%.
IMO, WD uses a trick to fool Crystal Disk Info, or the app is inaccurate.
What do you think?

 

[fzabkar]

CrystalDiskInfo is reporting what the drive is reporting. Can you show us the report from WD's Dashboard?

 

[CountMike]

I just checked 2 of my portable SSDs. Both of their TBW is 600. One is WD Blue SSD 3D and another one is Sandisk Ultra SSD 3D. The Crystal Disk Info shows me something very wrong.

https://imgur.com/7Ml6LdF

https://imgur.com/CfRzKFK

As you can see above, WD has written more than Sandisk, but the lifespan still 99% remains whereas Sandisk indicates 98%.
IMO, WD uses a trick to fool Crystal Disk Info, or the app is inaccurate.
What do you think?

Lifespan/health is an arbitrary function, specially for SSDs, based on TBW estimate and usage as well warranty and time to it's end, It's up to program's developer to interpret it. Disks can go bad and/or die even when 101% healthy. There's no program or anybody that can predict that. As long as SMART table is normal, you can be reasonably sure it will last long time.

 

[universalrule]

CrystalDiskInfo is reporting what the drive is reporting. Can you show us the report from WD's Dashboard?

Here you go, but it looks not so much different. The only thing is that the health state of the Q drive is normal in WD Dashboard whereas it has 2 yellow warning sign in Crystal Disk Info.

https://imgur.com/kI0ac8t

View: https://imgur.com/kI0ac8t

https://imgur.com/jC5AxnN

View: https://imgur.com/jC5AxnN

 

[universalrule]

Lifespan/health is an arbitrary function, specially for SSDs, based on TBW estimate and usage as well warranty and time to it's end, It's up to program's developer to interpret it. Disks can go bad and/or die even when 101% healthy. There's no program or anybody that can predict that. As long as SMART table is normal, you can be reasonably sure it will last long time.

I have 15 SSDs, but luckily none of them has any issue since 2019. I don't use front port nor USB hub for the portable drives. I also have 5 HDDs, and 2 of them have issues even though I've taken care of them carefully.

 

[USAFRet]

98% vs 99% could also just be a rounding margin.

98.4 = 98
98.7 = 99

That number in CDI is not meant to be an absolute.

 

[fzabkar]

I would have liked to have seen the attribute values, particularly Media Wearout Indicator (MWI).

SanDisk

• Average P/E Cycles = 0x9 = 9 (decimal)
  
  MWI = 0x0205005A0205 -> 0x0205 / 0x005A / 0x0205 -> 0x02 0x05 / 0x00 0x5A / 0x02 0x05 -> 2.05% / 0.90% / 2.05%

WD

• Average P/E Cycles = 0xA = 10 (decimal)
  
  MWI = 0x013601000136 -> 0x0136 / 0x0100 / 0x0136 -> 0x01 0x36 / 0x01 0x00 / 0x01 0x36 -> 1.54% / 1.00% / 1.54%

I believe that the MWI is encoded in 3 parts as ...

• % wear (worst case) / % wear based on P/E cycles / % wear based on TBW

In both cases the rated number of P/E cycles appears to be 1000. For example, in the WD case a P/E cycle count of 10 is 1% of 1000, and for SanDisk a count of 9 is 0.9% of 1000.

As for TBW, in the WD case we have ...

• 42920 GiB x (100 % / 1.54%) = 2993 terabytes

Therefore, the rated TBW appears to be 3000 TB. I expect that 600TBW is used for warranty purposes.

However, applying the same logic to the SanDisk case we have ...

• 30356 GiB x (100 % / 2.05%) = 1590 TB

I have no explanation for the difference.

 

[universalrule]

I would have liked to have seen the attribute values, particularly Media Wearout Indicator (MWI).

SanDisk

• Average P/E Cycles = 0x9 = 9 (decimal)
  
  MWI = 0x0205005A0205 -> 0x0205 / 0x005A / 0x0205 -> 0x02 0x05 / 0x00 0x5A / 0x02 0x05 -> 2.05% / 0.90% / 2.05%

WD

• Average P/E Cycles = 0xA = 10 (decimal)
  
  MWI = 0x013601000136 -> 0x0136 / 0x0100 / 0x0136 -> 0x01 0x36 / 0x01 0x00 / 0x01 0x36 -> 1.54% / 1.00% / 1.54%

I believe that the MWI is encoded in 3 parts as ...

• % wear (worst case) / % wear based on P/E cycles / % wear based on TBW

In both cases the rated number of P/E cycles appears to be 1000. For example, in the WD case a P/E cycle count of 10 is 1% of 1000, and for SanDisk a count of 9 is 0.9% of 1000.

As for TBW, in the WD case we have ...

• 42920 GiB x (100 % / 1.54%) = 2993 terabytes

Therefore, the rated TBW appears to be 3000 TB. I expect that 600TBW is used for warranty purposes.

However, applying the same logic to the SanDisk case we have ...

• 30356 GiB x (100 % / 2.05%) = 1590 TB

I have no explanation for the difference.

Aha...it makes sense. But it's funny, because Sandisk Ultra 3D must be the same as WD Blue 3D as far as I know. I heard the label is only different, but it's not true, I think.
Thanks for the explanation!

 

[fzabkar]

Yes, they look the same.

https://www.elvikom.pl/dysk-ssd-wd-...-prosba-o-identyfikacje-elementow-t66662.html

https://www.techpowerup.com/review/sandisk-ultra-3d-4-tb-ssd/2.html

Maybe the difference has something to do with the firmware version?