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.
Spoiler: These cards didn’t hold a candle to SanDisk’s.
This card failed the criteria that I set out for determining what’s considered a name-brand card, for a few reasons:
- It came in “retail” packaging (although it didn’t have a UPC or EAN on it that could be scanned by a point of sale device), but that packaging didn’t identify the vendor who sold the card.
- It’s fake flash.
- The OEM ID and product name (in the card’s CID register) were set to dummy values (the OEM ID was set to hex
3456, and the product name was set to justSD.)
It does, however, meet the criteria to be considered a knockoff — since the brand name and logo are very similar to SanDisk — so these cards are going into the knockoff bin in my result set.
These cards were fake flash (as I suspected they would be when I bought them), with actual capacity being a little under 32GB.
On performance, this card was…not the worst I’ve seen, but still pretty bad — all measurements were below average. This card bears the U3, V30, and A2 marks — and performance measurements weren’t good enough to qualify for any of them (primarily because it fell just short of the 30 MB/sec sequential write speeds that would be needed to qualify for the U3 and V30 marks; it didn’t come anywhere near what would be required for the A1 mark, let alone the A2 mark).
On the endurance testing front, this card did about as well as I expected — which is to say, not well at all. Its first error was a 1,127-sector wide address decoding error during the very first round of testing. It started having more significant issues starting during round 1,395, when many of the last 64 bits of some sectors got stuck either on or off. (An odd failure pattern for sure.) It passed the 50% failure threshold during round 2,235 — at which point the endurance test was over.
Here’s the progression that this card took:
So overall? These cards are fake, they’re knockoffs, they didn’t perform very well, and their endurance was pretty bad. Don’t buy these.
November 3, 2025