What is UHS-II? Differences between UHS-I vs. UHS-II SD Memory Cards

If you’re in the market for a new SD card, you’ll run into quite a few specifications before choosing a correct SD card for your DSLR, video camera or drone. 

One of the more complex features the SD Association has released is Ultra High-Speed (UHS) bus interface. Evolving from normal SD card speeds (High-Speed), UHS SD cards has increased the potential data transfer speeds to meet the demands of modern high-speed devices.

What is Ultra High-Speed (UHS)?

Ultra High-Speed (UHS) is the new generation bus interface for SD cards. Succeeding the regular high-speed specification, UHS was recently designed to support devices with higher capacity and speed requirements.

In addition to handling higher memory card capacity, UHS standard raises the bar for faster data transfer rates, increasingly important when shooting high-resolution videos and large, RAW format images. To meet high demands of modern devices, UHS specification includes three versions: UHS-I, UHS-II, and UHS-III. These range in speed from an impressive 104 Mb/s to a jaw-dropping 624 Mb/s.

UHS SD Card Comparison Table

Differences between UHS-I, UHS-II, and UHS-II

UHS-I bus interface, with transfer rates up to 104 Mb/s, debuted as the first upgrade from normal, high-speed specification.

Next, came UHS-II, which bumped up the speeds to 312 Mb/s. Perhaps the most prominent difference from its first version, was the added 2nd row pins, which uses Low Voltage Differential Signaling (LVDS) technology to allow higher transfer rates.

Most recently, UHS-III specification was announced in earlier 2017, doubling previous UHS-II rates for insane data transfer speeds up to 624 Mb/s. UHS-III specification carries two lane, LVDS technology and uses new QR (Quick Recovery) function for improved power management to reduce its transition time from Dormant to Active. This optimizes your camera's power consumption, especially useful in shooting time-lapse, burst mode or extended videos. 

UHS-II SD Card Compatibility

What does this mean for me? 

As UHS-III is a fairly new specification, it may be a while until most devices adopt the standard. However, many manufacturers, such as, Nikon, Sony, Olympus, Fuji and more, have already integrated UHS-II into their newer cameras and card readers. 

Since Apple's shift to universal USB-C ports, newer MacBook models require Type-C dongles and adapters to connect other peripherals, including micro and SD cards. Many of these adapter's card slots do not support UHS-II or UHS-III standard yet. Even on newer 2017 models, iMac's native SD card slots are still not using UHS-II card readers. For now, only iMac Pro supports UHS-II SD cards. In other words, even if you are using an UHS-II SD card, you're still not able to fully experience upgraded speeds, unless you are using an iMac Pro. 

With newer SD card specs introduced into the USB-C realm, we’re left with the question of how to connect UHS-I and UHS-II micro and SD cards to our Type-C devices.

Is there a solution for this? 

Yes. With the Satechi Type-C UHS-II Micro/SD Card Adapter, now you're finally able to shoot brilliant 4K videos, capture high-resolution images and quickly upload to your Type-C device, using lightning-fast UHS-II speeds.

Transform your iMac's USB-C port into a UHS-II card reader slot, to fully experience the enhanced speeds of UHS-II standard. Or let our Type-C card reader travel with you! Keep one of our card readers in your camera bag, for viewing and uploading your exciting footage on-the-go through your Type-C smartphone, tablet or laptop. 

The adapter is supported on virtually any Type-C Gen 3.1 device and compatible with both UHS-I and UHS-II micro/SD cards, for speeds up to 312 Mb/s. Interested? Pre-order on our Satechi site here. Available on August 2nd, 2018. 

Type-C UHS-II SD Card Reader for MacBook Pro

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