SanDisk Extreme A2 UHS-I microSDXC card review

SanDisk offers dozens of different microSD cards, from cheap and cheerful basic options to premium UHS-II cards boasting super-fast data transfer speeds. The Extreme A2 sits roughly in the middle of the SanDisk microSD range. It's capable of 190MB/s maximum read speed and up to 130MB/s write speed - not record-breaking speed, but quick enough for the vast majority of microSD use cases. What's more, it also has an A2 rating, meaning it's able to load apps faster if you want to use the card in an Android phone (most microSD cards are only have the slower A1 rating).

Capacities for this A2 card include 64GB, 128GB and 256GB. It's a pity higher-capacity options aren't available, and be aware that the 64GB card has slower read/write speeds than the larger capacities (170MB/s read, 80MB/s write).

Read more: the best microSD cards

Performance

To verify SanDisk's speed claims, I broke out my storage benchmark testing software of choice: CrystalDiskMark. This can be configured to replicate a best-case read and write speed scenario, which should reveal the maximum possible speed a memory card, SSD or hard drive is capable of.

A 167MB/s max read speed is pretty much up there with SanDisk's 170MB/s claim for the 64GB capacity card. 67.5MB/s is a little short of the advertised 80MB/s, but isn't too far off.

But benchmarking software isn't real-world usage, so I also ran a more representative tests transferring files to and from the drive. I used a folder of images totalling 25.7GB, as well as one large 36.2GB file, to test how fast the microSD card is when transferring multiple small files and a single large file (the latter will always result in faster read/write speeds).

In this real-world transfer speed test, the Extreme A2 was able to sustain 149MB/s when transferring a single large file from the card, with speeds peaking at 159MB/s - not far off the maximum read speed achieved in CrystalDiskMark. Write speeds were also almost the same as those recorded by the benchmarking software. As is always the case for any memory card, working with multiple image files of the same total data size results in slightly slower transfer speeds, but the speed hit isn't too noticeable.

Verdict

The SanDisk Extreme A2 microSDXC card strikes just the right balance of good-enough performance at a reasonable price. Unless you need to record high bit rate uncompressed 4K video, there shouldn't be many scenarios that this card couldn't handle. Whether you need a microSD card for your camera, action cam, dash cam or phone, this versatile offering is ideal and won't break the bank. Although we tested the 64GB card, I'd recommend going for the 256GB version. It's faster, costs less per gigabyte of storage than the lower capacities while still being affordable, and you'll soon use the extra capacity.