Jul 29, 2019 07:00:00

Products compatible with A1 standard of microSD card perform twice as much as the minimum standard and may exceed products compatible with A2 standard

Jeff Geiling, an engineer

who claims that there is no point in improving performance in 'A2 standard compliant' of microSD card, and actually showed no difference by benchmark test, this time benchmarks A1 standard compliant products And found a new difference.

Raspberry Pi microSD follow-up, SD Association fools me twice? | Jeff Geerling
https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-follow-sd-association-fools-me-twice

What Mr. Gering noticed before was that there was not much difference in performance when comparing the microSD card that says A2 standard compliant with the slightly older microSD card that doesn't support that standard. The SD Association of the standards group specified that the minimum standard of the A2 standard is '4000

IOPS for random read', '2000 IOPS for random write', and '10 MB per second for sequential write'. MicroSD card did not clear this criteria.

Engineers claim that there is no point in improving performance in 'A2 standard compliant' microSD card-GIGAZINE

Following this, Ms. Gilling conducted a benchmark by acquiring a microSD card compliant with the A1 standard, which is not as fast as the A2, 'random read 1500 IOPS', 'random write 500 IOPS' and 'sequential write 10 MB per second' as the lowest standard.

The result is this graph. The “SanDisk Extreme Pro A1” compatible with the A1 standard is shown in blue. According to Geeling, the 4K reading score of the benchmark is 2514, the 4K writing score is 1203, and both are more than A2 standard compliant products, and they are more than twice as fast as the lowest standard of the A1 standard. The

In terms of speed unit price per dollar (approx. 109 yen) (IOPS / USD), A2-compliant products (US $ 15.49 and approx. 1680 yen) are read 122 and write 61. The A1 standard compliant products ($ 13.37 and approx. 1460 yen) are read 183 and write 88. The Samsung Evo +, which had good results in the benchmarks, purchased 322 three-year-olds, and 115 for 115, because the price was as low as $ 8.60 (approximately 930 yen).

According to Mr. Guering, A2 standard compliant microSD card will lose performance when combined with hardware that does not support command queue function that improves random read performance and cache function that improves random write performance. On the other hand, the A1 standard compliant microSD card is compatible with any hardware, and the random I / O performance remains the same. It's best to avoid buying, 'concludes Mr. Geling.