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USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

anandtech.com

41–50 of 279 posts

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#41

I am starting to see computers with USB C on the host side. The future of one single connector to rule them all will be here soon. Wait a minute, we already had that, it was usb 2.0?!?!

I never saw anyone hooking up a monitor via USB 2.0

I've seen them for sale on Amazon and elsewhere. I always thought they'd be neat to throw in a supplemental kit bag for a second display on the go. I think some of the smaller ones were even bus powered.

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#42

I am starting to see computers with USB C on the host side. The future of one single connector to rule them all will be here soon. Wait a minute, we already had that, it was usb 2.0?!?!

USB-A/B for USB2.0 lacked the pin-count to provide compatibility with other connector standards by using a passive adaptor (except a few like PS/2). It also lacked the data bandwidth to encapsulate many other connector electrical protocols when using an active adapter except a few like RS-232 and 100mbps Ethernet. It also couldn’t deliver much power either - 500mA at 12V is only 2.5W - enough for a mouse or webcam.

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#43

Earlier quoted context omitted.

Nope. Much simpler. Just enabling the use of the other data lanes that were already in the cable waiting to be used one day. USB-C has 4 differential twisted pair data lines.

That sort of explains why USB cables have been getting more expensive. More copper.

Probably more like "better tolerances" or something like that. The labor/time put into a cable is the most pricey part, raw materials are probably only a few cents, even if you double the copper into it.

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#44
post #21

Earlier quoted context omitted.

I'm honestly surprised that they haven't rebranded USB 2 into USB 3.2 Gen 0 and USB 1 into USB 3.2 Gen -1.

Would USB 1.1 be USB 3.2 Gen -1.1 or USB 3.2 Gen -0.9? Hmm...

Neither. It gets to be USB 3.2 Gen -1 Plus.

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#45
post #9

Does this also mean that soon every computer will be making noise/radiating waves around 40GHz? Can someone with more depth in this area shine some light on this?

Is tinfoil-hatesque EMF poisoning real? I personally believe that it is real (just go camping where there's no service and you'll feel better) but it's hard to prove without decades of study and money, which won't happen because there's so much money to be made. There are other reasons why camping makes you feel better. Earthing/grounding gets you in touch with the earth's natural schumann resonance (through the canv…

Could that just be the feeling of being outdoors, and away from distractions for a while?

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#46
Honestly, I'm waiting for old USB(USB A, USB B) to be deprecated and USB C become the new universal USB. As in ATM machine, you get the drill. Current USB cable situation is a mess - my phone is USB C, but it came with a USB A to USB C cable. Good thing I can connect it to my 2017 MacbookPro using it's original USB C charging cable! However then I can't charge. Sometimes I use a USB C to female USB A dongle to use my phone's USB A male to USB C. And the whole thing has become expensive, good USB C cables seem to be made out of gold. Life would become so much easier if everything was USB C to USB C

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#47
post #5

I’d love to ditch HDMI (even on my television!)

I'm actually really happy with HDMI. It doesn't change much, has good compatibility and doesn't confuse a video cable for anything else. To me its universality makes it better than display port. My next PC will likely have 2 HDMI ports and that will make me very happy. Lots of USB for other stuff but the speed won't be an issue there - no need for USB 4 data rates because... who needs it?

Oddly, DisplayPort had no royalties and the later revisions had chaining support. So HDMI won over the PC world but DisplayPort and DVI didn't win over the TV world, possibly due to not having DRM by default, afaik.

On a tangent, I did see a ~2004 DVI projection-screen tv at a thrift shop once but I couldn't figure out how to get it to output audio. Then it hit me, it uses regular old RCA cables!

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#48
post #18

As someone who knows next to nothing about how USB actually works and just uses it, what goes into making each USB generation faster? At the physical layer, is it the materials in the cables are getting better? Or new ways of using the same materials? At the protocol layer, is it newly developed computer science theory being applied or is it just old fashioned pragmatic engineering iteration, looking at usage and mak…

I'm no means an expert but up to USB 2.0 there were 4 pins (2 for power and 2 differential signals for bidirectional data) With USB 3.0 they added 4 more signals for separate transmit/receive. Initially they used 8b/10b encoding and then switched to 128b/132b encoding. They also increased the signaling rate with each generation. Also in the USB 2.0 and earlier the higher level protocols were kind of inefficient with…

> With USB 3.0 they added 4 more signals for separate transmit/receive

So is it not actually serial any more?

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#49
> ... it will not be exactly Thunderbolt 3 as its functionality will likely be different.

I don't understand how this isn't simply ratifying/renaming current TB3-on-Type-C-connectors and this cryptic sentence in the page doesn't help. Anybody know?

This isn't to say that such a renaming might not be a good idea! But it would be nice to know if my current Type C ports with TB and DB support were in fact already "USB 4.0."

Also: speaking of nomenclature: notice that according to the press kit slide show, USB 3.1 Gen 2, USB 3.2 Gen 2x2, and USB4 all have the same "Alternative Branding": "Super Speed+". Madness!

Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB

#50

tl;dr: Intel made Thunderbolt 3 royalty free in 2018, so now it's essentially being adopted as USB4. I had to look up what the point of 40Gbps was, and the industry evangelization site https://thunderbolttechnology.net/ explains that it will allow driving one 5k display or two 4k displays, which is not possible with the 20Gbps offered by USB 3.2 or Thunderbolt 2. This also helps external GPUs, where TB2/USB3.2 is the…

Does 40Gbps mean two 4K displays daisy chained?

In theory, yes. Since driving one 60hz 4k display at 4:4:4 chroma takes roughly 18gbps then daisy chaining 2 displays should be possible.
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