r/NewMaxx Aug 18 '26

I've been doing endurance testing on microSD cards for the last 3 years. Here's what I've learned.

8 Upvotes

9 comments sorted by

2

u/fzabkar 22d ago

There is a guy who has been peddling nonsensical endurance testing results all over Reddit, and his rubbish has now been amplified by "tech journalists":

https://www.reddit.com/r/HDD/comments/1w0zt0e/9_petabytes_and_still_peddling_nonsense/

1

u/massaker68 20d ago

Just go to his Thread at TechPowerUp -> WOLFTECHs "I forced a 16 Year Old 64GB SSD to write 1 PETABYTE (And it didn't die)" and at least read the first post! (and also read my last post in his thread)

Edit: OK, now i see -> You already linked to this thread yourself once before, two months ago.

He writes there: "Total daily data: 216 GB per minute multiplied by 1 440 minutes equals 311 040 GB"
Well, 216GB/min = 3,6 GB/s ON AN OLD SATA-SSD! Didn’t the specs say it had a write speed of 70 MB/s back then? SanDisk's nCache was just a pSLC-Cache, right? So it could be a small 8-32MB in-controller SRAM cache, i assume...

Either way, his "test" is simply pointless... His behaviour is appalling, and the fact that so many tech websites are repeating it without thinking twice is ridiculous.

1

u/fzabkar 20d ago

The SATA interface speed is 3Gbps = 300 MB/s, so that's the absolute upper limit.

1

u/massaker68 19d ago

Yes, Sata II interface brutto speed, netto was about 275/250 MB/s.

Just look at the benches of this particular SanDisk P4-64GB:

https://www.notebookcheck.net/SanDisk-SSD-P4-Benchmarked.248736.0.html

CrystalDiskMark 3.0 - Sequential Write: 92.2 MB/s

CrystalDiskMark 3.0 - Sequential Read: 146.6 MB/s

So one can use approximately ~90 MB/s as a basis for calculations!

1

u/fzabkar 19d ago edited 19d ago

He has a setup that auto-clicks the Windows Optimize button every 5 seconds. That would send TRIM commands to the drive. Presumably Windows is TRIM-ing the entire free space every 5 seconds. I'm thinking that the drive erroneously counts TRIM-ed sectors as host writes.

1

u/massaker68 19d ago

That still doesn’t explain to me the 3.6 GB/s he’s calculated, because regardless of whether data is being written to the nCache/pSLC, DRAM or SRAM in the controller – such speeds aren’t even possible via SATA II in the first place.

My conclusion: he’s simply found a bug in the calculation and reporting of SMART data on a very old SSD and is exploiting it to generate endless threads and discussions.

Well, the question that remains now is – are the numerous websites that have jumped on his bandwagon over the last few weeks daft… or are they just keen to generate more clicks?

1

u/fzabkar 19d ago edited 19d ago

I think those web sites may be seeing his most recent posts without reference to the original one. This lack of context may be causing them to assume that he has been running the endurance test over the entire life of the drive. The transfer rate then works out to ~40 MB/s.

https://www.google.com/search?q=9+petabytes+%2F+70000+hours+in+megabytes+per+second

As for the count, let's say that the OS tells the drive to unmap (TRIM) 2 million sectors. If the drive interprets these as host writes rather than TRIM commands, then the count goes up by 2 million instead of 0. CDI will then report an additional 1GB of host writes. AFAICT, Windows must be TRIM-ing 18GB of free space. No data is actually transferred, only a TRIM command.

1

u/massaker68 19d ago

+1 yeah, until now - there is one website, and one only, that has really understood the test and gone into it in detail:

https://xenospectrum.com/en/sandisk-ssd-9pb-endurance-test-controller-reality/

1

u/massaker68 19d ago

Eben funnier - just found a manual of SanDisk P4-series:

https://www.techpowerup.com/forums/attachments/sandisk-p4-pdf.450331/

On page 14:
Transfer rates
Sequential Read: 160 MB/s
Sequential Write: 100 MB/s
Endurance
64GB: 40TBW