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I've just bought a used SanDisk 480GB SATA SSD and I'm wondering whether any of the numbers displayed in SMART are bad please?

In Active@ KillDisk Ultimate it shows "SMART warnings" on the disk (not shown on the screenshot below). Here is the SMART info:

Is this just saying there are warnings because it doesn't recognise the last attribute, 244? I see 0 is displayed in amber.

Obviously the Power Cycle Count is 10x higher than the Power-On Hours Count - which I guess isn't great? (4426 vs 432)

The Unexpected Power Loss is almost the same as the Power Cycle Count - which I'm guessing is also not good? (4237)

How do I interpret the numbers in:

Attribute #. Name Value
165 Average Erase Count 2382
166 Minimum W/E Cycle 11
168 SATA PHY Error Count 53
169 Total Bad Block 234
173 Wear Leveller Worst Case Erase Count 11
187 Reported Uncorrectable Errors 16
230 GMR Head Amplitude 1616
233 Media Wearout Indicator 5410
234 Unknown Attribute - is this GB written? 26805

Are any of these numbers bad?

Here is the report from CrystalDisk Info:

The firmware on the SSD is up-to-date according to SanDisk SSD Dashboard.

I ran both the short & extended SMART test in SanDisk SSD Dashboard, which passed.

Here is the SMART data from SanDisk SSD Dashboard:

ID Name Value Threshold Health
5 Re-assigned Sector Count 0 None N/A
9 Power-On Hours Count 436 None N/A
12 Drive Power Cycle Count 4426 None N/A
165 SLC Block Erase Count 2382 None N/A
166 Minimum P/E Cycles 11 None N/A
167 Maximum Bad Blocks per die 0 None N/A
168 Maximum P/E Cycles 53 None N/A
169 Total Bad Blocks 234 None N/A
170 Grown Bad Blocks 0 None N/A
171 Program Fail Count 0 None N/A
172 Erase Fail Count 0 None N/A
173 Average P/E Cycles 11 None N/A
174 Unexpected Power Loss Count 4237 None N/A
184 End-to-End Error Detection/Correction Count (EEEDC) 0 None N/A
187 UECC Count 16 None N/A
188 Command Timeout Count 0 None N/A
194 Temperature 105.8ºF 41ºC None
199 SATA CRC Errors 0 None N/A
230 Media Wearout Indicator 6.80% None N/A
232 Available Reserve Space 100% 4% excellent
233 NAND GB Written 5410 None N/A
241 Total GB Written 2088 None N/A
242 Total GB Read 4252 None N/A
244 Temperature Throttle Status Off None N/A

I think they used the SSD for photography stuff before, but I'm not sure. I do know that they used it on a Mac previously with the HFS+ filesystem (it's still formatted as this at the moment).

It's an internal SSD. If it had have been an external SSD then I might understand the Unexpected Power Loss number, if they had just unplugged the USB cable without doing a Safely Remove Hardware & Eject Media first (or whatever the equivalent is on Mac).

I can always return this disk if it looks like it might at all be dodgy, but I could do with some help interpreting the numbers please - so I know what to tell the seller. Any help is much appreciated - thanks!

Amazon Dies In Darkness
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Danny Beckett
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1 Answers1

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It looks fine. There's been zero (grown) bad blocks, 100% 'spare' capacity is available. Total wear at this point is little over 6%, or 6.80% to be precise (derived from RAW data 0x06, 0x50 in attribute 0xE6).

Total Bad Block being > 0 while Grown Bad Blocks = 0 means those reported at Total Bad Blocks are so called 'early bad blocks' (see for example: https://us.transcend-info.com/embedded/technology/bad-block-management).

Only value that may raise an eyebrow is the high number of unexpected shutdowns but it is unlikely this is a flaw of the drive itself.

Use the SanDisk Dashboard to perform a secure erase, the unexpected shutdowns should be of no consequence then: Unexpected shutdowns can for example cause 'translator' errors (in translator or FTL that maps LBA to physical blocks of NAND).

As secure erase or sanitize will basically take the drive back to it's initial state with a fresh FTL, whatever issues may have arisen from unexpected shout-downs are gone. You can compare to getting rid of NTFS file system errors by creating a fresh file system by means of re-formatting the drive. Of course it will not have an effect total LBA's written (wear).

I suppose it's a matter if you feel comfortable relying on a used drive. The SMART statistics give no reason for concern, and even when bought new you'd reach same wear level within reasonable time anyway. There's no objective reason to not trust this drive IMO.

With regards to 'reputable sources': The most reputable source would ideally be the manufacturer of the SSD (or drives in general) that openly and honestly publish their SMART specifications. Only very few do and that's why the general public is often just largely guessing or relying on blogs that every now and then shed some light on SMART related issues (disclosure: DiskTuna.com website is maintained by me, I used it as example because it's easy for me to do without doing a Google search).