Another exampler of corporate bulls**t. LG seems incapable of getting a simple fact-sheet right, so the customer doesn't know what he will get and what will work and what doesn't.
- Why would they leave Thunderbolt out of the tech specs if it was there? So I guess it won't be Thunderbolt.
- Unclear: 2x USB 3.0 downstream sound like USB 3.0 = 3.1 gen1. Why wouldn't they make those 2 connectors gen2 if the USB-C needs to be gen2 to offer 4k @60Hz.
- If it's gen1 it's limited to 5 gbps which wouldn't allow 4k at all, or am I wrong here?
What is unclear to me (and I couldn't find an explanation after googling): Does Displayport over USB-C work independently of the speed limits of the USB-specification? Are those DP-signals transferred in a different way when using Alternate Mode? What I mean is: Even if USB-C gen2 is limited to 10GBps and 4k 60Hz needs ~16 GBps, could that somehow work nonetheless?
This is such a mess. Companies not stating if 4k is @30Hz or @60Hz or which USB-version built in and what speed you get... Even if you know about all this stuff and possible problems it's often impossible to find any useful information after a lot of googling.
edit: After a lot of googling I finally found this: USB-C 3.0 (3.1 gen 1) supports Displayport 1.3 in Alternate Mode. And Displayport 1.3 supports "5Kx3K@60 and 4k@120Hz" over a single cable as stated in the VESA Documeatation (PDF) on page 10:
And from another VESA page:
Early implementations of DisplayPort Alt Mode USB Type-C devices will likely use existing DisplayPort 1.2a capabilities that support up to 5.4 Gbps per lane. Using 5.4 Gbps across all four high-speed lanes will support up to 4K (4096 x 2160) display resolutions at a 60Hz frame rate with up to 30-bit color.
Sorce: VESA® Brings DisplayPort™ to New USB Type-C Connector
The more I read about it, the more I'm bugged and stressed out. This is the worst documented technique I've come accross in a long time (except maybe Ebay's Java APIs ).