LTT has created true spec cables with the actual spec mentioned on the cables but they can not keep up with demand despite being expensive get sold out as soon as new stock comes in.
They are not TB5 compatible though, and if you are going to drive monitors through it, or connect external GPU, 120Gbit (TB5) is much better than 40Gbit TB4 gives you. If you are willing to pay a bit more, consider TB5 cables from CalDigit, StarTech, CableMatters, or Apple.
By chance, has anyone tested Cable Matters' cables?
I just bought a couple of their Thunderbolt™ 5 cables. They seem like a reputable company that would make their cables true-to-spec. Thanks in advance!
We had good results testing Cable Matters stuff here at work, but that was for non-critical use so I didn't go too hard on the tests. (Actually, I didn't go too hard on any of it since it was mostly make-work from a manager trying to cause trouble, but still....)
I was quite impressed by GlobTek (available at Digi-Key) and have been buying those when I need something nice. Their USB-C line are some of the best I've seen, not that I'm a connoisseur.
I bought a 3-meter long USB C cable from them for data and display transfer, which turned out to be the only USB C cable of that length capable of driving my display at its full resolution and framerate. However, after a year of use, it stopped transferring any sort of data. So while they're probably up to spec, the quality isn't necessarily what their pricing may suggest.
Support allowed me to send it back for replacement as a "one-time exception", though I was well within the common 2-year warranty period in the EU.
I've not spec tested them, but astronomy gear is notoriously picky about USB cables and since I switched all of my cables to cable matters a lot of weird behaviors just stopped happening
I can't say I've seen it on USB-C-esque cables (except maybe a thunderbolt cable a while back?) but I've seen some cables use a type of aluminum or mylar-looking foil between the outer rubber sleeve and the inner sleeves and wires.
That shield is a drain wire combined with either a woven braid (most effective at lower frequencies) or a solid aluminized mylar foil (most effective at higher frequencies), or, for the best cables, both together.
A USB-C cable really should be shielded. Here's a cross-section I took of a nice full-featured USB-C cable: https://ibb.co/svR5Yvyr . You can see the VBUS/GND (fat red/black), the SS pairs (white plus red/blue/yellow/brown, each one foil shielded on this cable), the USB 1/2 pair (white/green), and then the CC and SBU stuff is the remaining wiring. Notice how not just the whole thing is braid+foil shielded, but the SS pairs are individually shielded; that's really important at these speeds, and what you want to see on a good cable.
Compare with two USB 2.0 cables: https://ibb.co/BHz4v1mx and https://ibb.co/GfpJmgbx ; the first one has the shield braid, as it should, but everything else is nicer on the second one. Cables!
My concern is stiffer cables are likely more likely to rip USB ports off the PCB. A lot of devices provide very little support to the USB port which is basically just hanging off pads on the PCB, so a stuff heavy cable could provide a lot more bending force to rip it off.
Phones and macbooks have it done right where the outer portion of the port is built in to the device body, but most other devices don't do this.
This keeps needing to be pointed out every thread this appears on. Plenty of cables have eMarkers that claim "40Gbps" or whatever speeds, or support 240W PD...but absolutely cannot deliver either of those. And none of these consumer level testers can test either of those claims.
Resistance measurements can cursorily test claims of 240W but resistance changes with temperature which changes with current...so unless your tester puts 5 amps down the wire for 5 minutes and then tests resistance it's not a very good test.
Yeah — "the eMarker said 40Gbps" is basically the same problem as trusting the print on the jacket.
For home use I've ended up treating real capability as an empirical property of the specific cable+port+device combo: does this exact cable drive this monitor at the mode I want, under load, for an hour? If yes, it gets a colored heat-shrink band and never leaves that use case. Everything else is a phone/charge cable until proven otherwise.
Interestingly, I have found a very mixed bag of USB-C cables I've collected over the years to generally just work for all my use cases. I can charge my various USB-C laptops at 65W with all the USB-C cables I have on hand. Maybe it's just my habit of just buying cables from known brands (Belkin is normally my go to) but I also have random cables that came with various devices of varying quality and all these also work just fine. I have a 6-port charging hub so I can see the charging wattage and I can easily get 65W to various laptops and a high capacity power bank, regardless of the cable being used. All cables also work fine for data transfer, although I confess I use USB-C for data transfer rarely so it is possible there is some variability there. YMMV but I wonder how much of this issue is just crappy low-end cables?
Every not-broken USB C cable allows for 480Mbps USB 2 speeds and 60W charging. In USB C terms, it doesn't get any more basic than this; that's as low-and-slow the specification tolerates.
The issues come into play with going beyond that. USB 3 speeds? USB 4? Thunderbolt? DisplayPort (4k uncompressed video!) alt modes? 240W charging? These are all practical things that regular people use USB C cables for every day, but they require very specific support from the cables themselves, and that support is widely varied.
Your cables work fine for what you're doing with them, but you're really barely scratching the surface of the kinds of things that can be done. :)
Not that I disagree with you, but I _wish_ "regular people" used 240W charging every day. As far as I can tell it's still pretty niche and hard to get 240W chargers
It’s because you are using the lowest use case for usb (like most people). Literally everything can manage 65w power only.
All of these “usb sucks” posts are about using multiple 4k 120hz monitors dasychained while pumping 140w and a handful of other dongles hanging off which pushes usb to the limit and requires carefully selecting the highest quality cables.
This effectively only tells you what the E-Marker reports though, the actual capabilities of the cable are still unknown.
You can say the cable can do whatever you want on the E-Marker, its not the source of truth.
The problem is, to actually benchmark everything, voltage drop, resistance, actual bandwidth (especially at Thunderbolt 5 speeds) requires a lot of hardware.
I like your "who watches the watchers" reference, but AI's reviewing AI work, and notably, people reviewing people work, are subject to the same problem!
The same principles that worked for auditors tracking risk compliance in the 2000's now work for humans tracking AI-output risk compliance in 2026
This is the one I use and I quite like it. I've had it for a little over a year and a half. I used it to sort (or trash) all my cables and to test new incoming cables.
I just got this one a few days ago so it's kinda weird I've seen it mentioned or posted about multiple times since. Guerrilla marketing?
Anyway, it's definitely better than having nothing, and tests resistance as well. I tossed a couple low value/duplicate/high resistance cables because I've got too many just lying around causing clutter. Also helped 'confirm' my good (e.g. TB4+) cables that weren't labeled clearly are indeed good cables - granted, this is only as dependable as the marker chip the manufacturer added.
I'm not so sure about cheap. All the cheap ones I've tried have been pretty flaky, and ended up in the junk bin. I picked up this guy for work: https://bit-trade-one.co.jp/en/adusbcim/ and it's been pretty good. That was a while ago though, and some of the cheaper ones might have caught up.
Started using whatcable.uk app. Been amazing at finally knowing cable speed, but also device max speeds, and everything in between, without having to carry around one of those digital dongles with more limited use.
If you want a super fast cable and high power thats where they get pricey. "Charge only" cables can often be fairly cheap and perform well even for laptops and high draw devices.
Just measuring the power info is limited use. I'm sure there's value for some people, but I only need to keep track of 0-2 high power cables.
> Your no-brand 480Mbps USB 2.0 cable is indistinguishable from the super-fast USB 4 cable that can move 40 gigabits (around 5 gigabytes) of data every single second.
One of those is way thicker than the other, at least.
I would love for something to force a speed and power rating on USB-C plugs.
USB-IF certified is a certification that the cable follows the spec, but that spans usb 2.0-only cables up to USB4v2 cables. The tester shows you what the capabilities are.
The cables are supposed to be labelled with their maximum speed (5, 10, 20, 40, or 80 Gbps or nothing if no data) and maximum wattage (60W or 240W).
HOWEVER, I don't remember ever seeing a cable with such a label. I'm sure they exist, but I don't see them. Requiring products to be labelled, and treating mislabelling as fraud, could mostly solve this. It's definitely a real problem.
> Requiring products to be labelled, and treating mislabelling as fraud, could mostly solve this.
There are too many manufacturers to hunt. Basically USB-IF needs to stop almost all shipments in the world. That's not going to happen.
USB spec is completely open and free to obtain. While it allows people to develop and DIY many things, it also attracts bad manufacturers like flies.
Good certified cables with correct markings exist. There are companies like Cable Matters or Startech who bother to actually certify their cables and get USB-IF TIDs. They do cost you quite a bit money though. Here are some:
This is really good. The base is open source, and has both GUI and a CLI. For the purposes of this article, identifying what each cable can actually do, that’s covered. There’s additional Pro capabilities that you can pay for.
then you have a bunch of cables and wires that with all different types of connector that you can 'easily' identify which one is for which device. sounds familiar hah
re: https://randsinrepose.com/guides/usb/usb-guide.html
Apple sells this $30 (0.5m) CalDigit cable https://www.apple.com/shop/product/hs9d2zm/a/ and this $70 (1m) Apple cable https://www.apple.com/shop/product/mdw94am/a/
There's also some interesting discussion of Thunderbolt 5 cables on reddit (6 months ago): https://www.reddit.com/r/UsbCHardware/comments/1r84q54/
https://www.youtube.com/watch?v=Hfovjw7Ts_U&t=974s
I just bought a couple of their Thunderbolt™ 5 cables. They seem like a reputable company that would make their cables true-to-spec. Thanks in advance!
I was quite impressed by GlobTek (available at Digi-Key) and have been buying those when I need something nice. Their USB-C line are some of the best I've seen, not that I'm a connoisseur.
Support allowed me to send it back for replacement as a "one-time exception", though I was well within the common 2-year warranty period in the EU.
I can't say I've seen it on USB-C-esque cables (except maybe a thunderbolt cable a while back?) but I've seen some cables use a type of aluminum or mylar-looking foil between the outer rubber sleeve and the inner sleeves and wires.
A USB-C cable really should be shielded. Here's a cross-section I took of a nice full-featured USB-C cable: https://ibb.co/svR5Yvyr . You can see the VBUS/GND (fat red/black), the SS pairs (white plus red/blue/yellow/brown, each one foil shielded on this cable), the USB 1/2 pair (white/green), and then the CC and SBU stuff is the remaining wiring. Notice how not just the whole thing is braid+foil shielded, but the SS pairs are individually shielded; that's really important at these speeds, and what you want to see on a good cable.
Compare with two USB 2.0 cables: https://ibb.co/BHz4v1mx and https://ibb.co/GfpJmgbx ; the first one has the shield braid, as it should, but everything else is nicer on the second one. Cables!
Phones and macbooks have it done right where the outer portion of the port is built in to the device body, but most other devices don't do this.
If you want to test bandwidth, that's a five- or six-figure bit of gear.
Resistance measurements can cursorily test claims of 240W but resistance changes with temperature which changes with current...so unless your tester puts 5 amps down the wire for 5 minutes and then tests resistance it's not a very good test.
For home use I've ended up treating real capability as an empirical property of the specific cable+port+device combo: does this exact cable drive this monitor at the mode I want, under load, for an hour? If yes, it gets a colored heat-shrink band and never leaves that use case. Everything else is a phone/charge cable until proven otherwise.
I throw out every usb cable that comes bundled with devices because they are literal junk.
The issues come into play with going beyond that. USB 3 speeds? USB 4? Thunderbolt? DisplayPort (4k uncompressed video!) alt modes? 240W charging? These are all practical things that regular people use USB C cables for every day, but they require very specific support from the cables themselves, and that support is widely varied.
Your cables work fine for what you're doing with them, but you're really barely scratching the surface of the kinds of things that can be done. :)
My desktop “server” with two 4K monitors doesn’t even reach 240W !
All of these “usb sucks” posts are about using multiple 4k 120hz monitors dasychained while pumping 140w and a handful of other dongles hanging off which pushes usb to the limit and requires carefully selecting the highest quality cables.
You can say the cable can do whatever you want on the E-Marker, its not the source of truth.
The problem is, to actually benchmark everything, voltage drop, resistance, actual bandwidth (especially at Thunderbolt 5 speeds) requires a lot of hardware.
Using a USB-C Test Controller ($13,000), connected to a Pro Keysight Infiniium oscilloscope ($258,809) is the proper way to test it. https://www.keysight.com/au/en/product/N7018A/type-c-test-co...
https://news.ycombinator.com/item?id=47972511
To actually test for the bandwidth those are hell expensive.
Now people starting test for the chip, those scammers will install more fake chip ...
The same principles that worked for auditors tracking risk compliance in the 2000's now work for humans tracking AI-output risk compliance in 2026
This is the one I use and I quite like it. I've had it for a little over a year and a half. I used it to sort (or trash) all my cables and to test new incoming cables.
Anyway, it's definitely better than having nothing, and tests resistance as well. I tossed a couple low value/duplicate/high resistance cables because I've got too many just lying around causing clutter. Also helped 'confirm' my good (e.g. TB4+) cables that weren't labeled clearly are indeed good cables - granted, this is only as dependable as the marker chip the manufacturer added.
> Your no-brand 480Mbps USB 2.0 cable is indistinguishable from the super-fast USB 4 cable that can move 40 gigabits (around 5 gigabytes) of data every single second.
One of those is way thicker than the other, at least.
I would love for something to force a speed and power rating on USB-C plugs.
I bet there's at least one brand with extra–thick plastic insulation.
This already exists. Cable makers can certify their cables and mark them with their data speed and wattage.
I buy only certified, marked cables. If I see an unmarked cable, I assume it’s slow and low-powered…which is good enough for some things.
The cables are supposed to be labelled with their maximum speed (5, 10, 20, 40, or 80 Gbps or nothing if no data) and maximum wattage (60W or 240W).
HOWEVER, I don't remember ever seeing a cable with such a label. I'm sure they exist, but I don't see them. Requiring products to be labelled, and treating mislabelling as fraud, could mostly solve this. It's definitely a real problem.
There are too many manufacturers to hunt. Basically USB-IF needs to stop almost all shipments in the world. That's not going to happen.
USB spec is completely open and free to obtain. While it allows people to develop and DIY many things, it also attracts bad manufacturers like flies.
Good certified cables with correct markings exist. There are companies like Cable Matters or Startech who bother to actually certify their cables and get USB-IF TIDs. They do cost you quite a bit money though. Here are some:
https://www.cablematters.com/pc-1532-123-usb-c-20-charging-c...
https://www.cablematters.com/pc-858-123-usb-if-certified-usb...
https://www.startech.com/en-de/cables/1m-40g-usb4-cable
https://www.startech.com/en-de/cables/s2cepr1m-usb-cable
https://www.whatcable.uk