Analysis & Conclusion

If you need more than 32 GB of storage for your device that supports the full-sized SD card format, there is only one way to get it - get a SDXC (Secure Digital eXtended Capacity) card. However, not all SDXC cards are created equal. There are ordinary SDXC cards and higher-speed SDXC card that support the UHS (Ultra High Speed) bus.

The 256 GB Kingston Class 10 UHS-I SDXC Card not only offers a tremendous amount of storage capacity, it also delivers it at very high throughputs - up to 90 MB/s in read speed, and 45 MB in write speed.

Our copy and write tests show that Kingston was overly optimistic with the read speed but overly conservative with the write speed. The 256 GB Kingston Class 10 UHS-I SDXC Card delivered a sustained read speed of 77.7 MB/s and a sustained write speed of 64.4 MB/s. If you ask me, it was worth trading the read speed for a faster write speed.

Our IOMeter results, on the other hand, show that the 256 GB Kingston Class 10 UHS-I SDXC Card is optimized for large random and sequential reads, and large sequential writes, at the expense of everything else. That is really the right strategy because these flash memory cards are almost exclusively written to in large sequential blocks by your devices and either viewed (large random reads) or copied out (large sequential reads) to your computer.

Thanks to its phenomenal writing speed, the 256 GB Kingston Class 10 UHS-I SDXC Card will have no problem supporting 4K video recording by devices like the Samsung NX1 smart camera or the Panasonic Lumix DMC-GH4. Its large storage capacity will also allow you to record a lot more video than would be possible with lower capacity cards.

If you intend to record 4K video, you must absolutely get a card like the 256 GB Kingston Class 10 UHS-I SDXC Card. Otherwise, you should consider an SDHC card like the 32 GB Kingston Class 10 UHS-I microSDHC Card, which is fast enough for 1080p recording and is much cheaper to boot. In addition, more devices support SDHC cards than SDXC cards.

In recognition of its phenomenal sustained write speed and its humungous storage capacity, we think the 256 GB Kingston Class 10 UHS-I SDXC Card deserves no less than our Reviewer's Choice Award. Congratulations, Kingston!

Look for the lowest current prices on Kingston Class 10 UHS-I SDXC cards in Amazon or Pricegrabber!

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