The USB-C world just seems so confusing! So I can drive the monitor using HDMI, Display Port or USB-C, which have varying throughputs? Great.
Actually, a display connected via USB-C* is
always DisplayPort as far as the computer is concerned. 'USB-C displays' are effectively DisplayPort, (current) USB-C to HDMI cables incorporate a DisplayPort-to-HDMI converter.
Lets try and simplify the essentials:
- A USB-C cable has 4 pairs of wires to carry high-speed data, each of which can carry either USB 3 or DisplayPort - but not both. The cable also has a dedicated set of wires for old-school USB 2 as a fall-back.
- Current USB-C ports can only use 2 of those at a time for USB (one for out, one for back) - you'll only get 1 USB 3 port "worth" of USB bandwidth out of a USB-C port. The MacBook doesn't support the faster, 10Gbps USB 3.1 speed, either.
- A regular DisplayPort cable has 4 pairs, but doesn't always use all of them.
- An old-school 1080p display only needs 1-2 pairs, but a 4k display at 60Hz needs all four. Connect a 4k@60Hz display and the only capacity left for USB is the "fallback" USB2 facility.
So, on a USB-C hub/dock/multiport adapter:
- Any USB, Ethernet, SD card slots are sharing a single USB-3 port's worth of bandwidth
- They can do that alongside a 1080p or 1440p display - but connect a 4k@60Hz display and the other ports have to share one USB 2 connection...
A USB-C display with an integrated hub won't do 4k@60Hz
and be a USB
3 hub, either (the Apple/LG Ultrafine 4k display specifically says that the USB ports are 2.0 only - the 5k version is a thunderbolt display so different rules apply and it won't work with the MB).
NB: Yes, you can run 4k at 30Hz and halve the bandwidth - which might be fine for presentations or playing video (its not as if 30Hz LCD displays actually flicker at 30Hz) - but you wouldn't want that as a long-term solution for an interactive desktop: windows will jerk/tear as you drag them, the mouse pointer will disappear/flicker if you move it too fast...
My "standard" setup at home has power & 1080p monitor (today) plugged in at my desk.
Well, that should be OK - with a multiport adapter, the MacBook should manage a USB 3 drive and a 1080p display. Not that the Macbook is ever going to give you the smoothest, slickest experience you could ask for.
However, if you want to upgrade to 4k and/or multiple displays, or connect multiple external drives (and care about their performance) then, basically, the MacBook is not meant for you. Even disregarding the connectivity, you want something with a better GPU to drive multiple and/or 4k displays smoothly.
The MacBook - and the new Air - are designed for maximum portability, and its great that they
can be hooked up to a 4k display is great, but if that's your
primary purpose then you should be looking at the MacBook Pro.
* There are lots of ifs/buts/unlesses/ors/coming soons in the wider world of USB-C, of course, but I'm specifically talking about the non-Thunderbolt USB-C port in a MacBook here.