USB 4.0 "USB4" Specification Published

[uxmkt]

Protocol on top of protocol...
We already have the following mess:
- High-Speed USB (2.0)
- SuperSpeed USB (3.0)
...

Quoting Ramsay: https://www.youtube.com/watch?v=JmeAFNd-qE4

[davidbepo]

I hope it doesn't. That's a misfeature.

but why?

[carewolf]

but why?

Security issues.

[AndyChow]

Security issues.

I second this. I don't want random hardware that has direct access to PCIe lanes. I'm pretty sure they showed external thunderbolt "harddrives" can take over your computer, aka "Thunderclap".

I can also imagine a USB Killer type device that now fries your CPU directly.

[pegasus]

On the other side ... in 2010 you only had 40Gb in HPC cluster, in 2020 you'll have it on your desktop.

So it takes about a decade for tech to be ready for everyday consumer.

[ThoreauHD]

So.. what's changed between this and usb 3.2 protocol? This shit's really confusing. Asrock X570's have thunderbolt 3/usb 3.2 already. What's the 4 do?

[davidbepo]

I second this. I don't want random hardware that has direct access to PCIe lanes. I'm pretty sure they showed external thunderbolt "harddrives" can take over your computer, aka "Thunderclap".

I can also imagine a USB Killer type device that now fries your CPU directly.

welp, i guess thats a good reason

[anth]

The spec can be downloaded from https://www.usb.org/document-library...-specification

[tuxd3v]

So does this support PCIe or not? I think this was one major feature where it still wasn't clear which direction USB would take. I of course hope it does retain PCIe support from Thunderbolt! Everything else sounds great - especially the flexible bandwidth allocation.

USB 3.1 at least is very close, even in frequencies used,
You can see it by the PCIe raisers they use a USB 3.1 connector/cable, of 1 meter max( due to wave length, line impedance, etc).

What we see in a cheap way, is sending a pair of PCIe( x1 ), via USB 3.1 cables, but I believe no USB protocol is involved, only the communication Line is used( conector/Cable ), the protocol is PCIe..

I believe what you want is some PCIe 'pass-trough' USB, or PCIe encapsulated in USB packets?

[torsionbar28]

On the other side ... in 2010 you only had 40Gb in HPC cluster, in 2020 you'll have it on your desktop.
So it takes about a decade for tech to be ready for everyday consumer.

This is accurate. When I was building DEC Alpha supercomputers at DEC/Compaq in the late 1990's, those machines all had Gigabit Ethernet cards. They were large cards with a big heatsink on them. It was another decade before Gig-E would be a mass market consumer technology.

With NIC cards, power consumption and heat output are major factors. You can put a big heatsink in a server with screaming fans to cool it. Not so much in a consumer pc, or even worse, a laptop. Semiconductor lithography is a big part of this. As CPU's and GPU's move to smaller process node, older fabs are freed up to make things like NIC card chips. So yes it does take many years before the newest technologies can be economically shrunk down to operate cool enough for installation in consumer equipment.