SanDian (not to be confused with SanDisk) is a name that came up frequently while browsing though microSD cards on AliExpress. It’s very clear that they were attempting to trick buyers into thinking that they were SanDisk — offering a similar product lineup (Ultra, Extreme, Extreme PRO, etc.), using the same color scheme on their cards, and even copying the stylized “n” and “D” from the SanDisk logo. Given all the similarities, I decided to categorize these as “knockoffs”.
Spoiler: These cards didn’t hold a candle to SanDisk’s.
First off — these were fake flash (as I suspected they would be when I purchased them), with actual capacity being closer to about 32GB. Second, the manufacturer ID and OEM ID were set to all zeroes — a hallmark of a seller that doesn’t want anyone to know who made their cards for them.
On the performance testing front: they did pretty terribly, with all metrics scoring in the bottom 25% of all cards I’ve tested thus far. These cards bear the U3, V30, and A2 marks — and no sample scored well enough to qualify for any of these marks. On top of that, the SSR data didn’t indicate that it supported any of these speed grades — at best, it supports Class 4.
On the endurance testing front, the results I got were pretty consistent with low-quality flash:
Sample #1 started experiencing errors after completing just 41 read/write cycles, and the number of errors only increased as time went on. By the end of round 1,284, it had passed the 50% error threshold. Here’s the graph of this card’s progression:
Sample #2’s first error was a data loss error during round 663. It continued to progressively degrade until it got to just shy of the 10% failure mark, at which point it stopped responding to commands. Here’s what the graph of this card’s progression looked like:
Sample #3’s first error was a 32-sector wide data loss error during round 24. It survived a total of 1,938 read/write cycles before it crossed the 50% failure threshold (though it took a number of manual resets to convince it to keep working up to that point — which is part of the reason why it lasted longer than the other two samples). Here’s the graph of this card’s progression:
Overall? They’re fake flash, they performed below average in every metric, and they couldn’t go more than a few hundred read/write cycles before showing issues. These cards are trash. Don’t buy them — this is just someone looking to make a quick buck off of SanDisk’s name.
June 23, 2025