SD card
lastmod 2025-06-09created 2025-06-092 edits
Secure Digital, abbreviated as SD card, is a flash (non-volatile) memory card format developed by Matsushita, SanDisk, and Toshiba for use in portable devices such as digital cameras, handheld computers, PDAs, and GPS devices. As of 2021, SD cards are available in capacities from 8 megabytes to 128 terabytes. Cards with 4–32 gigabytes are classified as SDHC to distinguish their support for high capacity, and from 64-gigabyte products onward a separate standard called SDXC applies.
The format has proven very popular, but it can cause compatibility problems between older devices and newer cards of 32 gigabytes or more using the SDXC format, which can confuse consumers.
microSD
How reliable are microSD cards?
Results of a long-term, large-scale test based on real data
- microSD card reliability experiment run for about 1 year and 10 months on 256 cards of various brands/products
- 82% of all cards had at least one error; on average 2,400 read/write cycles until the first error, median 1,450
- At a 0.1% sector error threshold, nearly half reached the threshold within 4,500 cycles (mean) and 3,100 cycles (median)
- Durability varied widely by brand: Amazon Basics, Kingston, Kioxia (some), Lexar, OV, etc. were relatively good, while SanDisk, Silicon Power, Gigastone, onn., etc. were rated below average
- Regardless of brand, there were also many cases where off-brand cards showed results similar to or better than name brands
- Card failures occurred in various ways, such as write protection, CSD register corruption, corruption of all data, and power sequence failure
- Cards bought on Amazon showed better results overall than cards bought on AliExpress
See also
- HDD
- Flash memory