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SDHC UHS Speed Class 3 cards for 4K
  • SD Association have announced a new high-performance option and symbol specifically designed to support a wide array of 4K2K television and video products.

    A new Ultra High Speed (UHS) Speed Class 3 (U3) symbol will indicate products capable of recording 4K2K video and will operate exclusively on SDXC UHS-I and UHS-II memory cards and devices and SDHC UHS-I and UHS-II memory cards and devices.

    The UHS Speed Class 3 defines a sizzling fast 30 Megabytes per second constant minimum write speed to ensure high-quality video recordings. This means 4K2K video, live broadcasts and content can be recorded on high-performance cameras such as Digital Single Lens Reflex (D-SLR), Digital Single Lens Mirrorless(DSLM), camcorders and video cameras and then played back smoothly. Consumers will benefit from a single card that is capable of meeting all of their video, photo, music, document and data storage needs.

    “The world’s favorite SD memory card continues to evolve and meet shifting industry needs,” said Brian Kumagai, president of the SD Association. “Our new UHS Speed Class 3 standard will give consumers and businesses more flexibility and capability as the market shifts to 4K2K video formats. Both SDXC and SDHC memory card standards already offer the massive storage needed to support 4K2K video with enough room to store photos, music, documents and other data on a single portable card.”

    New devices offering the UHS Speed Class 3 will be backwards compatible and will work with existing SD memory cards.

    New standard speed between the memory card and the device can be up to 312 Megabytes per second.

  • 56 Replies sorted by
  • The German magazine "ct'" recently had an article on the status quo of both "UHS Class 3" cards and "UHS-II bus speed" support.

    The bottom line at the moment is that there is only one very expensive card reader (Panasonic AJ-MPD1G) on the market that supports UHS-II and only one SD card that claims to support the "UHS Class 3" sustained write speed of 30 MB/s (Toshiba Exceria Pro 32GB).

    It's amazing how much confusion the SD association is still creating with making people confuse bus speeds, peak transfer rates and sustained write speeds. And even the announced vapor-ware SD cards are slower than CFast cards that have been sold in quantities for quite some time now...

    (The ct' article is available online only behind a pay-wall)

  • Simple math exercise just for the fun of it… Assuming the standard format of consumer UHD cams will be 3840x2160 8bit 4:2:0 30fps, it'll have uncompressed bitrate of about 373 MBytes/s (2 986 Mbits/s). Compressed bitrate of 30 MBytes/s (240Mbits/s) would mean a compression ratio of about 12:1.

    For comparison, 1920x1080 8bit 4:2:0 30fps has about 94 MBytes/s (747 Mbits/s) uncompressed bitrate. Compression ratio of 12:1 would be achieved with 62 Mbps bitrate.

    Assuming that codecs in upcoming UHD cams are at least as good as h.264 on current consumer HD cams, and they indeed use 30MBytes/sec bitrate, the image quality could be quite usable.

  • @neokoo

    It is also good to understand that comparison can't be made in such way. As whole idea of lossy codecs is making losses were it is hard to see them :-)

    So, it is not necessary to proportionally increase bitrate at such resolution increase. Same is true for fps increase (due to vision nature and also due to much better motion predictor work).

  • @Vitaliy_Kiselev

    Indeed, I would expect that for scenes with only small amount of random detail the higher resolution would not necessarily demand equally higher bitrate.

    But with the usual torture test subjects like noisy high ISO images, fast moving water, crowds etc., shouldn't bitrate demand rise quite proportionally?

    I guess we'll know for sure when new era of UHD test videos comes to the web:)

  • Kingston Digital, Inc., the Flash memory affiliate of Kingston Technology Company, Inc., the independent world leader in memory products, today announced its fastest addition to the Secure Digital product line. The new DHC/SDXC UHS-I Speed Class 3 (U3) card (Kingston part #: SDA3/xxGB) allows professionals and consumers to capture 4K and other Ultra-HD video resolutions. The new card is available in 16 GB, 32 GB, and 64 GB capacities.

    The SD Association's latest specification, UHS-I U3 (Ultra High-Speed Bus, Speed Class 3), guarantees performance of at least 30 MB/s read and write, enough bandwidth to record and playback 4K video without interruption. Kingston's SDHC/SDXC UHS-I Speed Class 3 card provides speeds of 90 MB/s read and 80 MB/s write, which is up to 9x faster (read) and up to 8x faster (write) than standard Class 10 SD cards. The faster speeds ensure the best video and photo integrity by reducing stutter as well as faster PC upload time especially when using USB 3.0 card readers

  • image

    Today, SanDisk is announcing its latest flagship, the Extreme Pro SDHC/SDXC UHS-II. It exceeds the new UHS Speed Class (U3) spec, supporting continuous write speeds of up to 250MB/s. While the card is most appropriate for folks shooting 4K video, it'll also come in handy when you're snapping continuous RAW stills at high frame rates, letting you unload the camera's buffer just as quickly as you can fill it. The new cards will ship in April in 16GB to 64GB capacities, with prices ranging from $120 to $300. There's also a new U3 card reader that's designed to let you take full advantage of the SDXC card's 280MB/s transfer speeds. That device will also be available in April, with a $50 MSRP.

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  • I am guessing that they can't release the GH4 until these new cards are widely available, right? The GH4 isn't much good without these cards. Even the 100 Mb/sec 1080p mode would not work reliably without one of these new cards.

    Lets hope there isn't a delay in the introduction of these new cards.

  • Why do they even make 16GB versions in these high speed cards? One would think if you needed this speed you're recording with big files.

  • Why do they even make 16GB versions in these high speed cards? One would think if you needed this speed you're recording with big files

    And why not, if someone buys them? :-)

    In fact, SDHC card format is biggest hurdle in cameras performance. Due to interface and size.

  • @Vitaliy_Kiselev Do these new cards increase the possibilities for new better hack settings on the GH2?

  • Wouldn't be the "old" and famous Sandisk 64GB 95MB/sec SD card enough for 4k on the GH4 as we use it for stable 100Mb/s patches on the GH2?

    Or are we forced to use the new and more expensive cards?

  • Wouldn't be the "old" and famous Sandisk 64GB 95MB/sec SD card enough for 4k on the GH4 as we use it for stable 100Mb/s patches on the GH2?

    I have no idea, tests will show. As it can be that top camera write speed can not be reached on old cards. But it is pure speculation for now.

  • @Psyco

    There were modes that even the fastest class 10 cards would fail on the modified GH2's even at lower bit rates. There is a lot more to stability than purely just bit rate. There is a reason that these cards have speed maximums and minimums and not just a single constant rating for their speeds.

  • @mpgxsvcd The Sandisk 64GB 95MB/s was one of the cards all modes worked on (even with spanning) - going higher with the bitrate is more a problem of the SD card controller used in the GH2.

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    Panasonic is introducing new SDXC and SDHC UHS-I cards, the Gold Series “SDUC”, complying with UHS Speed Class 3 (U3) and suitable for 4K video recording. UHS Speed Class 3 (U3) is the standard announced in November last year by the SD Association responsible for establishing an SD card standard to respond to market needs for 4K video, defining a new Speed Class that guarantees a constant minimum write speed of 30MB/s.

    The Gold Series “SDUC” introduced by Panasonic can provide this UHS Speed Class 3 (U3) and is capable of stable and continuous real-time video recording at a minimum write speed of 30MB/s (240 Mbps). It can be used not only for unlimited 4K video recording in MOV/MP4 format, but is also capable of ultra high bitrate video recording at 200 Mbps (ALL-Intra) or 100 Mbps (IPB) for enabling smooth and beautiful high-quality video without the dropouts caused by an insufficient writing speed.

    With products not compatible with UHS Speed Class 3, the Gold Series cards are compliant with UHS Speed Class 1 or Speed Class 10 with a constant minimum writing speed of 10 MB/s (80 Mbps). The stable writing performance ensures highly reliable recording of low bit-rate 4K videos as well as Full HD and standard videos. Further, the Gold Series cards are a perfect match for the New LUMIX-G “DMC-GH4”, which is capable of providing awesome video quality for unlimited expressiveness.

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  • guys, what will be the card to buy for the GH2? Sandisc or Panasonic? With one 64gb how much footage can be recorded in 1080p/200Mbps and in 4k?

  • @olli66

    None of this cards are for GH2, just go to Sandisk cards topic :-)

  • I use fast Toshiba Exceria cards all the time for 70 mb/s video. Excellent and quite cheap to buy. I think they may work with GH4.

    Don't buy the hype that such cards should be $100 or more.

    Exceria's may do. And they are a lot less.


  • sorry, typo, of course I meant the gh4


    64GB Kingston for $107, seems like a better deal than Sandisk. Kingston vs Sandisk, any comments Re: reliability?

  • @Mistas

    It all depends on specific cards, but Sandisk is known as best option usually.

  • I recently got the 16gb Kingston. HEre are the disappointing results (considering the promise of 80MB/s for write.

    Sequential Read : 77.865 MB/s
    Sequential Write : 45.856 MB/s
    Random Read 512KB : 72.244 MB/s
    Random Write 512KB : 3.441 MB/s
    Random Read 4KB (QD=1) : 8.312 MB/s [ 2029.3 IOPS]
    Random Write 4KB (QD=1) : 0.867 MB/s [ 211.6 IOPS]
    Random Read 4KB (QD=32) : 8.209 MB/s [ 2004.2 IOPS]
    Random Write 4KB (QD=32) : 0.782 MB/s [ 190.9 IOPS]

  • I recently got the 16gb Kingston. HEre are the disappointing results (considering the promise of 80MB/s for write.

    Thing here that results can be inaccurate as you need proper USB writer that fully support this new standard.