The latest flash-based SD memory cards with UHS-I deliver up to 63 MB/s throughput. Users who want to exploit that performance need to pay attention to a few details, like making sure they upgrade to a USB 3.0 card reader. Which card is the fastest?
This test scenario may not be entirely relevant, but it shows the cards’ ability to handle concurrent read and write operations. You might want to copy all of the existing photos from your SD memory card and, at the same time, write a few gigabytes of data to it.
First things first: the speed rating doesn’t tell you too much about an SD card’s ability to execute sequential read and write operations simultaneously. The new Kingston Ultimate XX cards do extremely well, but all other cards in the top third of the lineup don't have much in common.
The SanDisk Extreme does well. The newer Pro model is just above-average. And even other high-end products like Lexar's Professional 133x, a Class 10 card, don’t convince in this extraordinary discipline.
