Apple usb-c to HDMI seems to support 3840x2160@60

[stormxu]

Just notice the updated instruction at https://support.apple.com/en-us/HT206587

says:

"With macOS 10.12 or later, MacBook (2015 and later) and MacBook Pro (2016 and later) support these resolutions and refresh rates over HDMI 1.4b using the USB-C Digital AV Multiport Adapter:

• 4096x2304 at 48Hz refresh rate
• 3840x2160 at 60Hz refresh rate (mirroring is not supported at this resolution)

"

Can anyone confirm this? Also what is the usb-A speed then? I am planing to buy a 3840x2160 monitor for my non-tb MacBook Pro 2017. If apple's dongle can support this, It would be great (no need to use a port to dp)

 

[campyguy]

HDMI 1.4 does not support UHD @60Hz. Apple's adapter is a passive adapter.

Consider an active adapter, one that supports HDMI 2.0 and, therefore up to UHD @60Hz. Accell Cables makes active adapters for both the mDP and USB-C port configurations to HDMI 2.0a.

 

[MrX8503]

That will not support 4K @ 60hz.

The problem is bandwidth. You won't find any multi adapters (that I know of) that will support 4K @ 60Hz unless it's TB3.

 

[campyguy]

TB3 carries DP 1.2, just like the MBPs all do going back years. DP 1.2 conveys plenty of relevant throughput/bandwidth for UHD @60Hz with the correct adapter. Like I wrote in my OP, Accell makes a mDP>HDMI 2.0 adapter that handles 4k @60Hz - I've got several in my offices for our displays waiting for Kaby Lake PCs and Macs…

Specifically, this adapter, under $40 - QED:
https://www.accellcables.com/products/mini-displayport-1-2-to-hdmi-2-0-adapter
Accell makes other adapters like this with different input interfaces, and their products are on the DisplayPort.org product portal unlike most of the junk out there. And, Apple's cables/adapters haven't gone through the certification process - Accell's relevant products have. Cheers.