After 40 hours of research and testing over the past two years, we found that the 64GB Samsung EVO Plus is the best microSD card for most people's needs. It's the most versatile and cost-effective microSD card of the 15 we tested this year. The EVO Plus's speedy random read and write speeds are ideal for phone and tablet use, and its sequential write speed is fast enough for shooting 1080p video.

If you already have a microSD card that fulfills your needs, you probably don't need to upgrade. The EVO Plus isn't leaps and bounds better than anything that's been available for the past few years. However, if you're having issues with the speed of your card—say, you want to shoot 1080p video and it can't keep up, or stored apps aren't running well—upgrading is a good idea.
The most important features of a microSD card are speed, price, reliability, and warranty. In a phone or tablet, apps often save data in small chunks scattered across the card, so a microSD card needs to be fast at reading and writing small bits of data in random locations. Sequential speeds—how fast the card can read and write long strings of data in a row—are less important than 4KB random speeds on phones and tablets but are still significant.

After making a list of the 15 most promising microSD cards—and considering only Class 10 U1 and U3 cards with a 64GB capacity—we tested each card's performance in an ASUS ZenFone 2 using A1 SD Bench. Using a USB 3.0 card reader in a laptop's USB 3.0 port, we also ran CrystalDiskMark, a benchmarking program designed to test sequential and random read and write speeds on solid-state storage. Between each test, we reformatted each card using the recommended utility from the SD Association to stabilize performance.

Source: Engadget