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SanDisk Extreme Pro SDXC UHS-II Card: Does Not Perform (45 ≠ 280)

SanDisk Extreme Pro SDXC

SanDisk claims up to 280MB/sec read speed for the SanDisk 64GB Extreme PRO SDXC UHS-II card. That speed sounded appealing as a primary card for testing new cameras, fast downloads, etc.

But surprisingly, the card runs at half the speed of my SanDisk ExtremePro 95 MB/sec cards, e.g this 64GB SanDisk card (highly recommended).

Those older and much cheaper cards download at ~90 MB/sec in a fast USB3 card reader whereas the “faster” card maxes-out at 45MB/sec!

I tried two fast USB3 card readers as well as the built-in slot on the late 2013 MacBook Pro Retina. I also tested the entire card capacity for reads and writes and reliability. While reliable, the card would not go faster than ~45MB/sec for reads or writes. Whereas the “slower” 95 MB/sec cards always hit 90+ MB/sec.

Perhaps the card performs in some special way in some specific UHS II device but as I would use it, my download speeds are half as fast as the older cheaper cards I already have. A reader reports similarly disappointing results with the SanDisk UHS-II card, even with the SanDisk Extreme Pro SDHC/SDXC UHS-II Card Reader/Writer (which has its own issues).

Card standards have changed over time, and “faster” has meant “slower or incompatible” in the past. In this case, it just means slower in all my usage scenarios. Claims and specifications are one thing, actual results are another, so unless a camera and card reader actually benefit, there is no point to paying more than twice the price for half the performance.

Some readers report faster operation in the Fujifim X-T1, but none have as yet confirmed any comparison with the 95MB/sec SanDisk card. Many cameras are limited by things other than card speed. As the 95MB/sec cards provide all the camera performance I need, my main interest is download speed.


As per SanDisk.

  • 64GB Storage Capacity
  • UHS Class 3
  • Optimized for UHS-II Devices
  • Max. Read Speed: 280 MB/s
  • Max. Write Speed: 250 MB/s
  • Water / Shock / X-ray Proof
  • Built-in Write-Protect Switch
  • Supports Advanced Shooting Modes
  • Downloadable RescuePRO Recovery Software

Axel P writes:

I had the same experience four weeks ago—no benefit in reducing the transfer speed, round about 45mb/s max! Half of the older Extreme Pro. P.S. I hope that this post will prevent disappointment for other readers !

DIGLLOYD: this kind of post is one of those things I very much like to do when I’m not writing for my subscribers, who make it possible. It’s a juggling act (time).

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