4 ms·

It's certainly much less bad now than it used to be, but the existence of "x1" connections (half lane count and bandwidth as its contemporary "x2" sibling) does

by usrusr 3y ago

It's certainly much less bad now than it used to be, but the existence of "x1" connections (half lane count and bandwidth as its contemporary "x2" sibling) does undermine trust. Is a cable advertised with the number "20" really an x2 cable accurately described according to "Gen 2" metrics, or is it really just an x1 cable, daringly called "20" because that's what a gen 3x1 connection could achieve? Looking at the Wikipedia page I get the impression that the new naming simply ignores the x1 links. That's like an invitation for misleading product descriptions. Maybe it would have been helpful to assign slightly off but clearly confusion-resistent numbers to the x1 siblings? Perhaps taking a page from supermarket pricing, "4.99Gbps", "9.99Gbps", "19.99Gbps"?

lxgr 3y ago
> Looking at the Wikipedia page I get the impression that the new naming simply ignores the x1 links. Yes, and that probably makes some sense: All compliant USB-C cables (other than USB 2 only) need to have two high-speed lane pairs, i.e. four high-speed lanes in total. (I'm not sure why that's the case, i.e. whether the aim was to avoid further confusion or if it's required for orientation-reversible operation in some ports). Whether the host/device actually support lane bonding or not is arguably not really the cable's choice, so it makes some sense to specify whatever the cable would support in an optimal configuration (i.e. maximum number of lanes used at the maximum supported modulation rate).
- archagon 3y ago
  But you also need to know how fast your USB will be if you’re using DP alt mode in 2 lane mode.
  - lxgr 3y ago
    Yes, but "USB 10Gbps (except if using 1-2 lanes of DP alt mode; then USB 5Gbps)" is probably a bit too much text for a USB-C plug. And with USB 4 and dynamic bandwidth sharing between USB and DisplayPort on the same physical bus this would get even more complicated.
    - archagon 3y ago
      In that sense, I think the Gen1x1/1x2 terminology was a bit more informative. Though still completely terrible.
Dylan16807 3y ago
You're a bit mixed up. All USB-C cables have 4 high speed wire pairs (or 0). There's no such thing as a USB-C cable that limits you to x1. x1 or x2 is entirely up to the devices attached. So if a USB-C cable is advertising "20Gbps", you want them to be talking about x1, because that means it's a better cable. (And if it's not USB-C on both ends, then it's always x1. It's never ambiguous.)
- lxgr 3y ago
  Agreed on most points, but > So if a USB-C cable is advertising "20Gbps", you want them to be talking about x1, because that means it's a better cable. is not what the USB-IF recommends – to them, a 20 Gbps cable is one capable of 2x2.
  - Dylan16807 3y ago
    Right, I mean "want" in the pleasant surprise way, not in the being correct way.

by usrusr 3y ago

lxgr 3y ago

> Looking at the Wikipedia page I get the impression that the new naming simply ignores the x1 links. Yes, and that probably makes some sense: All compliant USB-C cables (other than USB 2 only) need to have two high-speed lane pairs, i.e. four high-speed lanes in total. (I'm not sure why that's the case, i.e. whether the aim was to avoid further confusion or if it's required for orientation-reversible operation in some ports). Whether the host/device actually support lane bonding or not is arguably not really the cable's choice, so it makes some sense to specify whatever the cable would support in an optimal configuration (i.e. maximum number of lanes used at the maximum supported modulation rate).

archagon 3y ago
But you also need to know how fast your USB will be if you’re using DP alt mode in 2 lane mode.
- lxgr 3y ago
  Yes, but "USB 10Gbps (except if using 1-2 lanes of DP alt mode; then USB 5Gbps)" is probably a bit too much text for a USB-C plug. And with USB 4 and dynamic bandwidth sharing between USB and DisplayPort on the same physical bus this would get even more complicated.
  - archagon 3y ago
    In that sense, I think the Gen1x1/1x2 terminology was a bit more informative. Though still completely terrible.

Dylan16807 3y ago

You're a bit mixed up. All USB-C cables have 4 high speed wire pairs (or 0). There's no such thing as a USB-C cable that limits you to x1. x1 or x2 is entirely up to the devices attached. So if a USB-C cable is advertising "20Gbps", you want them to be talking about x1, because that means it's a better cable. (And if it's not USB-C on both ends, then it's always x1. It's never ambiguous.)

lxgr 3y ago
Agreed on most points, but > So if a USB-C cable is advertising "20Gbps", you want them to be talking about x1, because that means it's a better cable. is not what the USB-IF recommends – to them, a 20 Gbps cable is one capable of 2x2.
- Dylan16807 3y ago
  Right, I mean "want" in the pleasant surprise way, not in the being correct way.