SanDisk is a well-known name in the flash memory industry. Founded in 1988, they developed the first flash-based SSD. They were later acquired by Western Digital in 2016, before being spun off as a public company in early 2025.
SanDisk is a name I’ve long been aware of, and one that — prior to this project — I was biased in favor of. I have a number of single-board computers that take microSD cards, and I typically defaulted to the SanDisk Ultra 16GB for their storage — and most of the time, had no issues with them. And since they’re such a major brand, I wanted to make sure they were properly represented in this project.
I ordered these particular cards in different batches. Sample #1 came from Amazon; samples #2 and #3 came from AliExpress. All three appear to be identical — including packaging, card artwork, capacity, and internal registers.
Sequential write speeds were definitely this card’s strong suit, with all three cards’ measurements clustered pretty closely together and scoring in the top 1/8 of all cards I’ve tested so far (as of the time of this writing). All other measurements, however, were just average. Comparing this to the package, however, tells a different story: the package advertises read speeds of up to 100MB/sec and write speeds of up to 90MB/sec — sequential read speeds made it about 7/8 of the way to the 100MB/sec mark, while sequential write speeds only made it about 5/8 of the way to the 90MB/sec mark.
These cards bear the U3, V30, and A1 marks. All performance measurements were good enough to qualify for the U3 and V30 marks, but all three fell short of the 500 IOPS required for the A1 mark. However, I’ll throw in my standard disclaimer: my performance testing methods do not align with those prescribed by the SD standard; perhaps they would have done better had they been tested under proper conditions.
On the endurance testing front:
- Sample #1’s first error was an eight-sector wide address decoding error during round 5,189. It has survived 17,052 read/write cycles in total so far.
- Sample #2’s first error was an address decoding error during round 118. It has survived 15,237 read/write cycles so far.
- Sample #3’s first error was an address decoding error during round 156. It has survived 12,990 read/write cycles so far.
June 26, 2025 (current number of read/write cycles is updated automatically every hour)