SanDisk Extreme microSDXC UHS-I Memory Card Review

To evaluate the performance of SanDisk’s Extreme microSDXC card, we plugged into a USB 3.0 FCR-HS3 card reader, connected to our Core i7-3960X / X79 Express-based test system, running Windows 8 Pro x64. In addition to monitoring performance during simple file transfers, we also ran a trio of benchmarks to see how the card handled different data types and transfer sizes. First up, ATTO’s Disk Benchmark.

As you can see in the image above, the SanDisk’s Extreme microSDXC card doesn’t hit its stride until the 64K mark, but when it does, performance actually exceeds SanDisk’s specified 80MB/s (read) and 50MB/s write speeds. According to ATTO, the SanDisk Extreme microSDXC card peaks at about 94.5MB/s and 61.7MB/s, for reads and writes, respectively.

CrystalDiskMark tells essentially the same story as ATTO. In this benchmarks, SanDisk’s Extreme microSDXC card tops out with 92.56MB/s and 61.45MB/s sequential reads and writes. Performance is also good in the 512K test, though the card struggles with smaller 4K transfers.

Finally we ran Anvil’s Storage Utilities SSD benchmark. This test is complete overkill for a microSDXC card, but if you want to full scoop on the SanDisk Extreme microSDXC card’s performance, there it is. As you can see, in the Sequential 4MB tests, the card has no trouble exceeding the speeds listed in card’s specifications.

We should also note that we monitored transfer speeds in a number of everyday usage scenarios, copying images and videos to and from the card, and it regularly exceeded SanDisk’s specifications. Read speeds of 88MB/s were common, with 58MB/s writes.


Marco Chiappetta

Marco Chiappetta

Marco's interest in computing and technology dates all the way back to his early childhood. Even before being exposed to the Commodore P.E.T. and later the Commodore 64 in the early ‘80s, he was interested in electricity and electronics, and he still has the modded AFX cars and shop-worn soldering irons to prove it. Once he got his hands on his own Commodore 64, however, computing became Marco's passion. Throughout his academic and professional lives, Marco has worked with virtually every major platform from the TRS-80 and Amiga, to today's high end, multi-core servers. Over the years, he has worked in many fields related to technology and computing, including system design, assembly and sales, professional quality assurance testing, and technical writing. In addition to being the Managing Editor here at HotHardware for close to 15 years, Marco is also a freelance writer whose work has been published in a number of PC and technology related print publications and he is a regular fixture on HotHardware’s own Two and a Half Geeks webcast. - Contact: marco(at)hothardware(dot)com

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