- Advertised capacity: 32GB
- Protected area: 83,886,080 bytes
- Fake/skimpy flash: Skimpy (0.27% skimp)
- Speed class markings: U3, V30, A1
- CID data:
- Manufacturer ID:
0x03* - OEM ID:
0x5344(ASCII:SD)* - Product revision:
0x80
- Manufacturer ID:
* This manufacturer ID/OEM ID combination are pretty well known to be associated with SanDisk.
| Card # | 1 | 2 | 3 | Average |
|---|---|---|---|---|
| Obtained from | Amazon | AliExpress | AliExpress | N/A |
| Price paid | $10.49 | $9.70 | $9.70 | $9.96 |
| Logical capacity | 31,914,983,424 bytes | 31,902,400,512 bytes | 31,902,400,512 bytes | 31,906,594,816 bytes |
| Physical capacity | 31,914,983,424 bytes | 31,902,400,512 bytes | 31,902,400,512 bytes | 31,906,594,816 bytes |
| Fake/skimpy flash | Skimpy (0.27% skimp) | Skimpy (0.30% skimp) | Skimpy (0.30% skimp) | N/A |
| Adjusted skimp | 0.0035% | 0.04% | 0.04% | 0.03% |
| Product name | 0x534d333247 (ASCII: SM32G) | 0x534e333247 (ASCII: SN32G) | 0x534e333247 (ASCII: SN32G) | N/A |
| Manufacture date | Apr 2020 | Sep 2023 | Sep 2023 | N/A |
| Serial number | 0x5340b8ea | 0xfb233772 | 0xfb233938 | N/A |
| Sequential read speed (MB/sec) | 76.73 | 126.87 | 151.46 | 118.35 |
| Sequential write speed (MB/sec) | 46.14 | 49.25 | 50.14 | 48.51 |
| Random read speed (IOPS/sec) | 2,097.00 | 2,668.37 | 2,606.13 | 2,457.17 |
| Random write speed (IOPS/sec) | 339.00 | 452.93 | 449.49 | 413.81 |
| Read/write cycles to first error | 5,215 | 74 | 70 | 1,786 |
| Read/write cycles to complete failure | 5,215 | Not yet determined | Not yet determined | 5,215 |
| Total days to complete failure | 160 | Not yet determined | Not yet determined | 160 |
| Card reader used | JJS CR-UTC4AC | JJS CR-UTC4AC | JJS CR-UTC4AC | N/A |
| Package front |  |  |  | N/A |
| Package back |  |  |  | N/A |
| Card front |  |  |  | N/A |
| Card back |  |  |  | N/A |
Discussion
Ok, it’s time to move on to one of my favorite brands.
Yes, I’m biased in favor of SanDisk. I’ve been using their microSD cards in some of my other projects for years (specifically, the SanDisk Ultra, usually the 16GB size) and have found them to be pretty rock-solid. That said, I wanted to try to be objective here. Additionally, before starting this project, my only experience was with the Ultras — I hadn’t used the Extremes or the Extreme PROs.
I’ll note here that I ordered these cards in different batches. The first batch came from Amazon, and consisted of one of each of the SanDisk Extreme and SanDisk Extreme PRO, in both the 32GB and 64GB sizes. The second batch came from AliExpress, and consisted of two each of the SanDisk Extreme and SanDisk Extreme PRO, in the 32GB size. Why order different sizes? Because SanDisk advertises different maximum speeds between the two. This version is supposed to get up to 100MB/sec read speeds, and 60MB/sec write speeds. Additionally, the 64GB model had the A2 mark, while the 32GB model had the A1 mark instead.
I think I got slightly different versions from the two sources: the version I got from Amazon has a product name of SM32G, while the two I got from AliExpress have a product name of SN32G. There’s also a noticeable difference in performance between the two: sample #1 only got about 3/4 of the way to the 100MB/sec mark, but samples #2 and #3 went well past it. (How did they do it? SanDisk apparently has some tricks up their sleeve — see the discussion on the SanDisk Extreme PRO 64GB for more info.)
How does this stack up against the other cards I tested? All three samples got above average scores in all performance metrics. Samples #2 and #3 got sequential read and sequential write scores that were more than one standard deviation above average. Sample #3’s sequential read speeds were actually more than two standard deviations above average. Sample #2 also got a random read speed that was more than one standard deviation above average.
This card carries the U3, V30, and A1 markings on it. The results I got are good enough to satisfy the requirements of the U3 and V30 marks; however, the A1 mark requires a random write speed of at least 500 IOPS/sec, and none of these samples met that requirement. Again, I’ll give my standard disclaimer of “perhaps this card would have done better had it been tested under proper conditions”. The two AliExpress samples were close enough to this mark that this could actually be true.
Endurance tests for two of the three cards are still ongoing:
- Sample #1 was doing great until the circuit breaker — to which the host machine was attached — tripped. After restoring power, all of the other cards attached to this machine resumed their testing just fine; however, this one decided that it was done. Admittedly, this made me a little sad, as this particular card had not experienced any errors up until that point. As I mentioned with the SanDisk Ultra 32GB’s, embeddedTS once did similar stress testing of some SanDisk cards and noted that they tend to be sensitive to brownouts — and with the way some of these SanDisk cards are going, I’m forced to agree.
- Sample #2 experienced an address decoding error after only 74 read/write cycles. It seems like it’s been particularly susceptible to address decoding errors — it experienced eight different ones over the first 1,031 read/write cycles. It has survived 4,370 read/write cycles in total so far.
- Sample #3 experienced an address decoding error after just 70 read/write cycles. It also seems like it’s been susceptible to address decoding errors, having experienced five different ones errors over the first 1,083 read/write cycles. It has survived 4,351 read/write cycles in total so far.
June 15, 2024 (current number of read/write cycles is updated automatically every hour)