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Unfortunately "USB 3.2" is just a version of the standard, which does not give any information about the performance of a USB port or device. USB 5 Gb/s = USB
by adrian_b 6mo ago
Unfortunately "USB 3.2" is just a version of the standard, which does not give any information about the performance of a USB port or device.
USB 5 Gb/s = USB 3.2 gen 1, available on Type A or Type C connectors (or on devices on a special extended micro B connector)
USB 10 Gb/s = USB 3.2 gen 2, available on Type A or Type C connectors
USB 20 Gb/s = USB 3.2 gen 2x2, available only on Type C connectors
Moreover, "5 Gb/s" is a marketing lie. The so-called USB of 5 Gb/s has a speed of 4 Gb/s (the same as PCIe 2.0). On the other hand, 10 Gb/s and 20 Gb/s, have the claimed speeds, so USB of 10 Gb/s is 2.5 times faster than USB of 5 Gb/s, not 2 times faster.
10 Gb/s USB and Ethernet have truly the same speed, but the USB overhead is somewhat higher, leading to a somewhat lower speed. However, the speed shown in TFA, not much higher than 7 Gb/s seems too low, and it may be caused by the Windows drivers. It is possible that on other operating systems, e.g. Linux, one can get a higher transfer speed.
- mbreese 6mo agoThe fact that you had to list all of the versions and speeds at the top of your post is illustrative of what the parent was trying to say. We can all look up what speed is associated with what version, but it’s not exactly a consumer friendly experience.
- adrian_b 6mo agoA few computer manufacturers do the right thing and they mark the speed on the USB ports, removing ambiguities, for example ASUS does this on my NUCs and motherboards. Unfortunately, there are too many who do not do this, even among the biggest computer vendors.
- riobard 6mo ago> mark the speed on the USB ports, removing ambiguities Unfortunately it's not true. Quiz: what happens when a device capable of 20Gbps is plugged into a port marked as 40Gbps?
- ziml77 6mo agoI can't tell if this is a trick question that has something to do with a quirk of USB running multiple lanes in parallel to get higher speeds. Because if not then it's the same as any specification for connecting devices that allows for multiple speeds. It runs at the lowest of the max speeds supported of everything in the chain.
- riobard 6mo agoThat's exactly the issue. I'm just pointing out that it's a fantasy to hope for simple numbering of max supported speeds will simplify the current USB mess. It will not. Consumers would expect plugging a 20Gbps device into a 40Gbps port should result in 20Gbps negotiated speed. In reality it will mostly likely end up at 10Gbps (or less) because of the mess.
- adrian_b 6mo agoOlder Thunderbolt devices were not compatible with USB, so plugging them into an USB Type C port would not work. Newer Thunderbolt/USB 4 devices do not have any technical reason for preventing them to work as USB 3.2 2x2, i.e. to work at 20 Gb/s when plugged into a 20 Gb/s host port, and vice-versa for 20 Gb/s devices plugged into a USB 4/Thunderbolt host port, because both Thunderbolt and 20 Gb/s USB need the same wires in the cable and connector. I do not know if all USB 4 controllers also work at 20 Gb/s (USB 3.2 2x2), but if they do not work that should be considered a bug.
- eqvinox 6mo agoUSB4/TB4 devices doing (only) PCIe tunneling will absolutely not work on a USB3.2 port, or even on an USB4 port without PCIe support (which you can find on some very recent smartphones I believe. It's spec compliant, PCIe is optional.)
- deleted 6mo ago[deleted]
- hypercube33 6mo agoThats just port speed, charging and other features are all a crapshoot on USB making Thunderbolt the sane version of the "USB-C" family where it requires a set of things (speed, charging wattage)
- repeekad 6mo agoThis is not what’s anti consumer, technical specifications can be confusing, it’s cable companies selling at Best Buy “gold plated” “HD ready” “braided fiber” “other bs” that is anti consumer. If you’re thinking about usb versions, you’re far from the normal consumer
- eqvinox 6mo ago> Moreover, "5 Gb/s" is a marketing lie. It's not a lie, the b just stands for baud not bit ;-)
- adrian_b 6mo agoThat is technically correct, but "b" has never been an accepted abbreviation for baud (which was Bd) and the naming of the first versions of the PCIe, USB 3 and SATA speeds, which were done by Intel, were obviously in contradiction with the industry standards and intended to confuse the customers. Previously to these standards promoted by Intel, the 1 Gb/s Ethernet used the same encoding and it was rightly called by everybody "1 Gb/s", not "1.25 Gb/s", because the gross bit rate has absolutely no importance for the users of a communication standard. Only Intel invented this marketing trick, calling PCIe 1.0 and 2.0 as 2.5 and 5 Gb/s, instead of 2 and 4 Gb/s, and similarly for USB and SATA, where e.g. SATA 3 is called 6 Gb/s, but its speed is 4.8 Gb/s. To be fair, what Intel did was not unusual, because in the computing industry there has been a long tradition of using fake numbers in marketing for various things, like scanner or video camera resolution ("digital" zoom, "interpolated" resolution), magnetic tape capacity ("compressed" capacity), and many others.
- Dylan16807 6mo agoThe Ethernet version would have been much sillier than that. The megabaud rates for 10/100/1000 Ethernet are in fact 20, 125, and 125.
- eqvinox 6mo agoYeah, it was a tongue-in-cheek comment. It's a shitshow, and I wish it'd backfire, but it won't. Maybe the EU will come up with some (better) "true labelling" laws, if not I see no chance for this to get better. (Why the current laws don't cover this, I have no idea. It's technically false advertising.)
- rewgs 6mo ago"gen 2x2" is Microsoft level bad naming.
- guax 6mo agoAnd USB gen 4x4 is for off-roading.
- mort96 6mo agoUSB 3.2 used to be what we now call USB 3.2 gen 2x2, doesn't it? So it used to be that the version dictated the max speed: 3.0 was 4Gb/s, 3.1 was 10, and 3.2 20, right? But then they decided to memory hole that and now USB 3.0 and USB 3.1 are also USB 3.2 and USB 3.2 is called "generation 2x2", whatever that is supposed to mean It makes no sense anymore. It used to be quite simple.
- Aerofoli 6mo agoNo, they just renamed things when new standards were released (3.1 and 3.2). 20Gbps wasn't possible before 3.2, and it called Gen 2x2 at the time of release. 5 and 10 Gbps were renamed, though. 5 Gbps first was USB 3.0, then 3.1 Gen 1, then 3.2 Gen 1. 10 Gbps first was 3.1 Gen 2, then 3.2 Gen 2x1. 3.2 Gen 1x2 is also 10 Gbps, but physically different
- Dylan16807 6mo agoDo any real devices use 1x2? I think we largely escaped that mess and it's mostly a strict progression of 5Gbps, 10Gbps, 10Gbps*2, 20Gbps*2, 40Gbps*2