Would it make sense to put a USB 3.0 hub into a 4K display?

[iBug2]

If Apple releases a 4K TB2 display, would it make sense to put a USB 3.0 hub inside? Wouldn't the 4K signal almost saturate the TB2 bus? How much bandwidth is left for USB anyway?

 

[AidenShaw]

If Apple releases a 4K TB2 display, would it make sense to put a USB 3.0 hub inside? Wouldn't the 4K signal almost saturate the TB2 bus? How much bandwidth is left for USB anyway?

All Dell 4K monitors have a 4-port USB 3.0 hub built-in (one high power charging port).

 

[brand]

All Dell 4K monitors have a 4-port USB 3.0 hub built-in (one high power charging port).

I fail to see how that is anything remotely related the the OP's questions since the USB hub in the Dell 4K displays has a USB3 uplink cable back to the computer. The OP was specifically asking about Apple's Thunderbolt displays where the USB uplink is done using Thunderbolt.

 

[AidenShaw]

I fail to see how that is anything remotely related the the OP's questions since the USB hub in the Dell 4K displays has a USB3 uplink cable back to the computer. The OP was specifically asking about Apple's Thunderbolt displays where the USB uplink is done using Thunderbolt.

I answered the thread title - yes, "it makes sense" and Dell is doing it. The title doesn't mention Apple or T-Bolt.

If Apple can't do it because they're using T-Bolt, then maybe T-Bolt is a mistake. Is T-Bolt already too slow for some useful setups?

If T-Bolt2 is too weak to do both video and USB, Apple could also make a cable with both mDP and USB 3.0 connectors, so that you have a single cable linking both ports. We know they have experience doing this (and making the cables a little too short).

 

[tomvos]

Apple has bundled several signals into one cable before.

E.g. my 30“ Cinema Display has only one cable coming from the actual display which splits into DVI, USB, FireWire and power at the end. Which is fine with me. They did the same before. Remember the ADC (Apple Display Connector) which had DVI and power in one connector. They routed the power through the graphics card (which was a bad idea to start with).

So I think, splitting USB 3.0 and Thunderbolt 2.0 into separate wires within the same cable is a perfectly reasonable approach to avoid the limit iBug2 mentioned.

 

[borad]

4K@60Hz uses about 11Gbps [EDIT: see comments below?]. Thunderbolt 2 has 20Gbps each way. That means you could hang all but the very fastest (SSD arrays, mostly) drive boxes off the monitor and not be capped. Note that the read speed from the box would have an uninterrupted 20Gpbs back to the computer (the monitor basically only using the channel away from the computer).

Thunderbolt 1 provided two channels of 10Gbps, and therefore just barely failed to fit in a 4K stream.

 

[iBug2]

4K@60Hz uses about 11Gbps. Thunderbolt 2 has 20Gbps each way. That means you could hang all but the very fastest (SSD arrays, mostly) drive box off the monitor and not be capped. Note that the read speed from the box would have an uninterrupted 20Gpbs back to the computer (the monitor basically only using the channel away from the computer).

Thunderbolt 1 provided two channels of 10Gbps, and therefore just barely failed to fit in a 4K stream.

Thanks. If the bandwidth required is 11Gbps, then Apple could easily carry a USB 3.0 signal over the same cable indeed.

 

[VirtualRain]

According to this bandwidth calculator, 4K can use as much as 16Gbps with overhead.

3840 x 2160 x 24 @ 60 Hz.
11.94 Gbit/s (ideal).
12.81 Gbit/s (CVT-RB).
16.02 Gbit/s (CVT-RB + TDMS 8b10b).

However, even if the display is using 16Gbps out the 20 that TB2 offers, that's only one way... so that would leave you with 4Gbps sending to your USB3 peripheral and a full 20Gbps receiving.