DHowett6 hours ago
Excellent article.
If I could offer one correction, it would be that SBU (as specified by the USB 3.0 Promoter Group[1]) means "Sideband Use" rather than "Secondary Bus".
On some devices, it is used to carry UART; on others, audio.
[1]: https://www.usb.org/sites/default/files/USB%20Type-C%20Spec%... (pdf)
altairprime5 hours ago
Their email address is under the Contact link in the header :)
1a527dd56 hours ago
Tangent: Author has this fabulous post I'd highly recommend: https://fabiensanglard.net/mjolnir/index.html
I read it once years ago and I come back to it every now and then wishing my current PC (10+ years and going) would gently die so I could finally build something small and tiny.
fabiensanglard5 hours ago
You know, accidents happen. If you were to trip over the carpet and that venerable PC falls in the dumpster.
floxy5 hours ago
I don't know what short-distance data communications will be like in 2050, but we know it will be called USB.
jasongill4 hours ago
USB-G 4.6 SuperSpeed Plus, but the cables will still just be used for charging your random electronics and won't even work for that half the time.
dotancohenan hour ago
I know not with what technology 2030 will use, but 2040 will use USB sticks and stones.
Neywiny6 hours ago
I actually like the 3.2 naming. Gen is speed, "by" is width. It puts it very roughly on par with PCIe's naming which nobody complains about. I just don't like that USB 3, USB 3.1, and USB 3.2 are the same things. And that sales people don't seem to understand that saying a chip supports 3.1 or 3.2 tells me it's anywhere from 5-20gbps which isn't ideal.
mistyvales6 hours ago
PCI-E has had the same standard since its inception: 1.0, 2.0, 3.0, etc. USB has changed multiple times and has remained confusing for the vast majority of people. What was 3.0 is now not 3.0. Even 3.1 has changed. There is no reason to use this naming convention they currently have but for some reason they stick with it..
kimixa6 hours ago
PCIe also had things like "1.1", "2.1" and "3.1" - that fixed issues and added functionality - but there wasn't the same crossover between "feature sets and spec revisions" and "speeds" we see in USB today.
mistyvales6 hours ago
Manufacturers of mainstream consumer motherboards never used 1.1, 2.1, etc. for PCI-E though. What is 4.0 on the spec sheet will be 4.0 to the buyer. My old 2016 motherboard has a slew of 3.0 labelled USB ports that are now not 3.0, hence the conundrum. It just doesn't make sense why they changed established naming conventions. Is this something that causes me sleepless nights? Not in the least. But it's still an annoyance for consumers and even advanced users as detailed in that latest Geerling video et al.
Neywiny6 hours ago
Possibly they stick with it because it's usable (ish) and it was driving everyone up the wall when they'd change it?
retired6 hours ago
And not only the sales people. Windows doesn't report anywhere what your motherboard is capable of, and even if you connect with a device it will not tell you the speed it agreed on.
151556 hours ago
Good sheet. Worth adding:
- Female vs male crossover naming and pinouts for Type-C connectors
- Actual voltage, modulation and signaling schemes (USB4v2 uses PAM3 11b/7t encoding)
- PD generations and profiles
mschuster916 hours ago
... and the bunch of proprietary voltage schemes like Quickcharge.
retired6 hours ago
Thanks to the EU those are now forbidden, all phones and laptops should be compatible with USB-PD.
Update: USB-PD is a requirement, but manufacturers are allowed to have their own proprietary charging solution.
pxeboot5 hours ago
I still don't understand why MacBooks support USB4/Thunderbolt 4/5, but NOT USB 3.2 Gen 2x2. So you can get 20-40Gb/s speeds with more expensive external disks, but only 10Gb/s with the cheaper, more commonly available ones that advertise 20Gb/s.
altairprime5 hours ago
I believe it’s that MacBooks support Thunderbolt primarily and USB only where absolutely necessary beyond what’s coded into one of the TB specs; and I assume TB doesn’t define 3.2x2x2 as part of any TB spec <=5?
conception6 hours ago
This article is why I replaced all the usb dock cables in the office to make sure the usb cable connected to the laptops was transferring enough power so the laptop wouldn't silently lower its frequency for the lower power draw. 10-30% speed bump just because.
dang5 hours ago
Related. Others?
USB Cheat Sheet - https://news.ycombinator.com/item?id=31271038 - May 2022 (168 comments)
maxloh6 hours ago
I once heard that the USB naming is misleading by design so that vendors could still sell older generations accessories they had in stock. The USB-IF just rebrands the old ones to make them sound current.
Imagine the following naming:
USB 3.0 / USB 3.1 Gen 1 / USB 3.2 Gen 1 -> USB 3 5Gbps
USB 3.1 / USB 3.1 Gen 2 / USB 3.2 Gen 2 -> USB 3 10Gbps
USB 3.2 Gen 2x2 -> USB 3 20Gbps
QuantumNomad_3 hours ago
I have a USB hub that I bought recently, that has very nice markings on it that are almost like you say :)
I connects via USB4 to the host, and has the following markings on its ports:
- Power in/USB 10Gbps
- USB 10Gbps
- USB 10Gbps
- 8K HDMI
Pretty happy with this one so far.
sgjohnson5 hours ago
> I think USB 4 is finally going to the right direction.
USB 4 is actually going into an even worse direction. USB 4 = Thunderbolt 4, except everything is optional. e.g. USB 4 might not even support DP Alt mode. Thunderbolt 4 always will.
brigade4 hours ago
Even backwards compatibility is optional in USB4. There are USB4 devices (SSDs at least) that will not function when connected to USB 3 ports.
kubik3696 hours ago
I think this practice is rather blatantly what you say. The same thing with HDMI forum folding HDMI 2.0 into HDMI 2.1. They made the new 2.1 features optional, therefore manufacturers were able to call their 2.0 devices 2.1 without actually supporting the 2.1 features. AMD has been recently doing similar things, releasing “new” generation of mobile processors where half of them are just rebrands of the older generation.
xzjis6 hours ago
Or it could be: 5 Gbps --> USB 3 10 Gbps --> USB 3.1 20 Gbps --> USB 3.2
Higher number = better
retired6 hours ago
The simplicity of Thunderbolt. Versions 1 and 2 used mini DisplayPort, 3 and upwards USB-C. Version 1 was 10Gbps, 2 was 20Gbps, 3 was 40Gbps, 4 was 40Gbps, 5 is 80 or 120Gbps with boosting.
A Thunderbolt 5 cable will always support 80Gbps, DisplayPort 2.1, PCIe, USB4 and power of up to 240 watt.
sgjohnson5 hours ago
> and power of up to 240 watt
Except active optical cables. None exist yet that I'm aware of though.
retired5 hours ago
I'd guess that most people who use optical Thunderbolt cables are aware that they do not carry power.
userbinator5 hours ago
IMHO USB 3.0 was the last sanely-named version. Then again, if you're familiar with Ethernet, the proliferation of variants isn't unexpected.
mahirsaidan hour ago
Great way of identifying the difference in types of USB
drob5186 hours ago
I’ve been a tech guy for 45 years and I still can’t figure out USB and Thunderbolt and what goes with what and how fast it’s supposed to run.
151555 hours ago
If you buy Thunderbolt 5 cables: every USB standard is compatible and then some.
ProllyInfamous5 hours ago
It wasn't until last year that I finally purchased my first USB-C device/cables – and after years of solid DisplayPort and Thunderbolt2 connections I absolutely hate USB-C (it's too delicate, physically).
Not until 2023 did I even have a computer newer than 2012, so I missed almost all of USB3's hayday — including nomenclature disputes — but the speeds sure are an improvement!
offbyone425 hours ago
I just wish product listings were clear and actually followed the specs.
AdamH121134 hours ago
This is generally good but it’s missing low speed (1.5 megabits/second), which is also under USB 1.1.
brcmthrowaway7 hours ago
Where does TB5 come into all of this?
syhol6 hours ago
- Thunderbolt 3 is a superset of USB 3.1
- USB4 is built on Thunderbolt 3's protocol, implementing a subset of its mandatory features
- Thunderbolt 4 is a strict profile of USB4 (all optional features made mandatory)
- USB4 v2 introduced 80 Gbps signaling
- Thunderbolt 5 is a strict profile of USB4 v2 (again, optional features made mandatory)
Neywiny6 hours ago
I don't see why it would. Thunderbolt is not a USB standard
aleph_minus_one6 hours ago
> Thunderbolt is not a USB standard
Concerning Thunderbolt 3: USB4 is based on the Thunderbolt 3 protocol [1].
Concerning Thunderbolt 4: "In July 2020 Intel announced Thunderbolt 4 as an implementation of USB4 40 Gbit/s with additional requirements, such as mandatory backward compatibility to Thunderbolt 3 and requirement for smaller notebooks to support being charged over Thunderbolt 4 ports.[14] Publications such as AnandTech described Thunderbolt 4 as "superset of TB3 and USB4" and "able to accept TB4, TB3, USB4, and USB 3/2/1 connections"." [2]
Concerning Thunderbolt 5: Intel considers Thunderbolt 5 as an implementation of USB4 Version 2.0. [3]
[1] https://en.wikipedia.org/w/index.php?title=USB4&oldid=134742...
[2] https://en.wikipedia.org/w/index.php?title=USB4&oldid=134742...
[3] https://en.wikipedia.org/w/index.php?title=USB4&oldid=134742...
Kirby646 hours ago
Thunderbolt 5 and USB4v2 are the same thing now. They both support 80gbps and pcie pass through.
aleph_minus_one6 hours ago
> Thunderbolt 5 and USB4v2 are the same thing now. They both support 80gbps and pcie pass through.
Not completely true: Thunderbolt 5 demands some capabilities that are optional for USB4v2.
Kirby646 hours ago
From a protocol/bandwidth level, it’s essentially the same though. Thunderbolt 5 has some more guarantees for power and display, but the data rate of the two is the same.
stevex6 hours ago
Doesn't it run over a USB-C shaped wire? If you're trying to understand things that plug into USB-shaped ports it seems at least worth mentioning.
DiabloD36 hours ago
To be fair: You should refer to these as Type-C cables, as they carry things that are not USB protocol.
The sole exception should be made for "charge only" cables, which can, and should, be referred to as "wired for USB 2.0". These cables "shouldn't" exist, but I also don't want to buy a $30 cable just to charge my phone.
stackghost6 hours ago
Thunderbolt 5 is basically just PCI Express, power delivery, and DisplayPort over the same cable, which for reasons passing understanding is terminated with a USB-C connector.
I think most of those cables will also support USB the protocol.
naveed1256 hours ago
nice work, thanks
aleksi15785 hours ago
[flagged]
fl4regun5 hours ago
You need to relax buddy, it's just a post on a web forum, why are you so angry?
_-_-__-_-_-3 hours ago
Don't call him buddy, guy.