Saturday, 22 Sep 2018

Satechi Slim Aluminum USB-C : A nice USB-C hub with a quirk or two

Earlier, we published a preview of the Satechi Slim Aluminum USB-C hub with HDMI. As said before, it’s a sleek device, milled from a single thin block of aluminum, which makes it sturdy as well as light (44 grams/1.55 oz), actually lighter than the product description on Amazon says.

Satechi USB-C hub, official product shot
Satechi USB-C hub, official product shot

One of the first things we do, is see if it charges at full speed. It doesn’t. The picture below shows two parts:

Measurement of power via Satechi USB-C hub
Above: MacBook charging with the Apple 89W USB-C charger. Below: the same, but with the Satechi hub in between.

As you can see, when the Apple charger is connected straight to the MacBook Pro, it charges with 19.7 ✕ 4.21 = 83 watts (rounded). With the Satechi hub in between, it charges with a maximum of 19.7 ✕ 2.4 = 47 watts (rounded). And indeed, when we check out the detailed product description halfway the product page on Amazon, it says so: “MacBook Pro 2016 power output: 49W”.

Note that this doesn’t have to be a problem: one of our editors uses a 45 Watt charger for whole days. The power consumption of a 15″ MacBook Pro usually sits around 10W. An external display brings that to 25W and if you heavily use the CPUs, spikes to about 60W. So it might happen that the laptop dips into the batteries for very short periods. You have to decide if you think that’s a problem but personally, we don’t worry about it.

Stability when moving files around

The next couple of tests focus on transferring files.

File test 1: is there a performance difference between copying to a drive without and with the hub in between? With or without the hub in between, copying 1 gigabyte of data to our USB stick took about the same time, roughly 13 seconds.

File test 2: connect two flash drives, then simultaneously copy a big file to each of them. This also worked fine.

File test 3: download a large file over WiFi, then copy a large file to a flash drive connected to the USB-C hub. No problems detected here.

During the file tests, the hub gets warm but not hot. You can still comfortably hold it, though.

Charging devices

We also tried charging an iPhone 6 Plus from the hub. In principle, a USB 3.0 port can supply 4.5W (5V ✕ 0.9A). We measured a power usage of 3W. It’s not a big difference, but the ports apparently do not charge with the full speed. If you connect the iPhone 6 Plus directly to the USB-C port of the MacBook Pro, it will charge more than twice as fast: 7W (5V ✕ 1.4A).

When idle, the hub uses 0,5W. Some notebooks, like the MacBook Pro, continue to provide power to the hub when sleeping (i.e. lid closed), regardless whether the notebook receives power or not. So if you’re traveling and need every drop of juice, disconnect that hub.

About that video output

One very interesting aspect on USB-C is its capability to route a video signal. The current standard has readily apparent limits: a 4K monitor can only be driven with a refresh rate of 30 Hz, instead of the usual standard 60 Hz.

Monitor hooked up via Satechi hub
Display hooked up via the hub (product shot from Amazon)

We hooked up the hub to our Samsung U28E590DS. This is an uncomplicated but cheap 4K monitor that has two inputs: a DisplayPort that’s capable of 60 Hz and a HDMI input that is limited to 30 Hz (like the hub). We hooked up the monitor to the hub, and it works quite well on macOS. There are no problems with attaching/detaching the cable on the fly.

Whether you like viewing your desktop at 30 Hz, that is another story. Most people would notice that the cursor movement isn’t smooth, that’s one thing.  But otherwise it’s not bad per say — there is only a limited number of things that would make it unusable. Most videos on YouTube are limited to 30 Hz, most movies are shot at 24 Hz and the usual office applications don’t have much animation in them.

However any action games are out of the question, and some newer YouTube videos are shot at 60 Hz, like this one: Mario Kart 8 World Record 60FPS. And besides that, some people might feel that it’s a big waste not to use their monitor at its full capabilities.

Note that for displays less than 4K, USB-C hubs are perfectly capable of using HDMI at the full 60 Hz.


The Satechi Slim Aluminum USB-C hub with HDMI is a very small and light-weight hub.

If you want to use it as a permanent dock at home, you should be aware of its limitations: like any USB-C hub, it’s limited to 30 Hz when hooked up to a 4K monitor. And it limits power to the laptop to a maximum of 49W.

If you’ll be using it while moving between desks, or traveling in general, then we think it’s a great device. It’s got two USB-A and an HDMI port, it looks good and it’s pretty cheap.

Satech hub tucked away under the desk
Although the captive cable is short, it’s still possible to tuck away the hub under a desk with a bit of velcro or something