The SD card association just announced a new spec called UHS Speed Class 3 for SDHC and SDXC cards. This new spec defines a minimum transfer rate of 30MBps and is aimed at 4K video streams.

In short UHS-I defines an interface speed that maxes out at 104MBps and UHS-II raises that to 312MBps but that is just the reader to card rates. UHS-x says nothing about what the flash itself can supply, that is for the Speed Class addendum. The U with a number in it is the Speed Class(SC), the numeral below it signifies the UHS version.

Stunning visuals are not part of the SD spec

So the new bit today is Speed Class 3 devices that specify a minimum transfer speed of 30MBps or 240Mbps, not a bad number really. Both UHS-I and UHS-II have SC3 defined, as do SDHC and SDXC formats. Both are a good thing, the only problem that remains is the SC Association still forcing royalty bearing Microsoft BS patents on us. The more things change…S|A

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Charlie Demerjian

Roving engine of chaos and snide remarks at SemiAccurate

Charlie Demerjian is the founder of Stone Arch Networking Services and SemiAccurate.com. SemiAccurate.com is a technology news site; addressing hardware design, software selection, customization, securing and maintenance, with over one million views per month. He is a technologist and analyst specializing in semiconductors, system and network architecture. As head writer of SemiAccurate.com, he regularly advises writers, analysts, and industry executives on technical matters and long lead industry trends. Charlie is also available through Guidepoint and Mosaic. FullyAccurate

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