2021 microSD Card Update

It's been a while since I checked contemporary microSD cards for audio performance. (See my original article on microSD cards for audio.)

A quick refresher: Streaming audio directly from microSD media requires difference performance criteria than for transferring large files. In the latter case, if one read out of thousands or millions takes substantially longer than normal, it's not really noticeable. For streaming and mixing polyphonic audio, one late read can starve a buffer and produce an audible glitch. Many of today's "fast" cards are optimized for file transfers and seem to occasionally pause for housekeeping, making them not so great for use in Robertsonics audio players.

For this reason, I devised a test that can be run on a WAV Trigger that measures the critical characteristics of a card. I haven't tested cards for some time, so I recently purchased a number of microSD cards from Amazon and ran my test on them. Interestingly, the big brand names were about what I expected, while a couple of brands I'd not heard of before pleasantly surprised me. I thought I'd share the results.

Of those that I purchased, the Silicon Power 3D NAND 32GB card was the clear winner, both in terms of performance as well as price. I've actually never tested a card that performed this well. Out of a million random 4K reads, no single read took longer than 711 microseconds, over multiple tests. Combined with the fact that it's currently available on Amazon at 2 for $12, or 10 for $55, it's an obvious choice.

The Delkin V10 32GB is a bit more expensive at $11, but is also a great card for audio. No single 4K read took longer than 890 microseconds over multiple 1M read operation tests.

Obviously, there are hundreds of microSD cards available that I have not tested, but this recent batch of cards seems to suggest that at least some manufacturers are moving in the right direction with regards to performance.