• xep@fedia.io
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    2 months ago

    Yes, this is incredibly annoying and it’s also the reason why some USB cables cost more than others, even they may look the same superficially.

    • FierySpectre@lemmy.world
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      2 months ago

      One of those cables that don’t work is rated for like 120W, with gigabit transfer speed… But it refuses to transmit display… Like bruh

        • zarenki@lemmy.ml
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          2 months ago

          USB-C video is usually DisplayPort Alt Mode, which uses a completely different data rate and protocol from USB.

          Even using old 2016 hardware, a computer and USB-C cable that both only support 5 Gbps USB (such as USB 3.1 Gen 1) can often easily transmit an uncompressed 4K 60Hz video stream over that cable, using about 15.7Gbps of DisplayPort 1.2 bandwidth. Could go far higher than that with DP 2.0.

          Some less common video-over-USB devices/docks use DisplayLink instead, which is indeed contained within USB packets and bound by the USB data rate, but it uses lossy compression so those uncompressed numbers aren’t directly comparable.

        • FierySpectre@lemmy.world
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          2 months ago

          Didn’t really think about that one but you’re right damn… (Looked it up, and it depends on the bit depth etc, but it’s around 3.2Gbps for the display settings if I’m correct)… So that explains a lot

      • tobogganablaze@lemmus.org
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        2 months ago

        That sounds like a dedicated charging cable. So yeah, they will (if at all) only transfer data slowly and not support any extras features like displayport.

          • tobogganablaze@lemmus.org
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            2 months ago

            No USB cable has “gigabit speed”. It probably has 480 Mbps (USB 2.0 standard).

            Maybe he meant a 5 Gbps Gen1 cable. That would be “gigabit speed” but still rather slow by today’s standards and won’t support DP. They are pretty cheap these days, so wouldn’t be suprising to see left over stocks being sold as charging cables.

            • tal@lemmy.today
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              2 months ago

              No USB cable has “gigabit speed”. It probably has 480 Mbps (USB 2.0 standard).

              What? I’m either misunderstanding you or this statement isn’t correct. Having USB cables that can move data at gigabit rates has been common for quite some years.

              Here’s the latest stuff:

              https://en.wikipedia.org/wiki/USB4

              Bitrate

              20 Gbit/s
              40 Gbit/s
              80 Gbit/s
              120/40 Gbit/s asymmetric

              • tobogganablaze@lemmus.org
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                2 months ago

                What? I’m either misunderstanding you or this statement isn’t correct

                I meant that no USB standard actually has exactly 1 Gbit/s. I even mention that next one if 5Gbit/s. Just a misunderstanding I think.