HDMI was supposed to be our saviour, but now DisplayPort threatens its dominance. What's the difference? For the average user - nothing. They both carry high-fidelity video and audio at resolutions higher than the human brain can interpret. Unless you are trying to pump 8K streams 5cm from your eyeballs at 200Hz, you're not going to notice the difference between the standards. They both do surround sound which your home cinema speakers are woefully under-specced for.

The main differences boil down to:

• DisplayPort has a spring-loaded latching mechanism which prevents cables coming loose.
• Lots of laptops and phones support DisplayPort via USB-C's DP Alt Mode.
• DisplayPort monitors can be "daisy chained" to each other.
• HDMI supports ARC (Audio Return Channel) which means your screen's sound can be sent back down the HDMI cable to an amp.
• DisplayPort uses Packetized Data Transmission which, in theory, is more efficient than HDMI.

But, in the end, it all comes down to this:

• What port your screen has.

My USB-C Docking Station has two DisplayPort outputs and a single HDMI socket. My 4K Vertical Monitor has DP, but my older monitor is stuck with HDMI. Is there anything I can do to convert the DisplayPort signal from my USB-C hub into an HDMI signal the monitor will understand?

Yes!

The good folks at Benfei have chucked me a couple of their adapters to test out. Let's put them through their paces.

Here's their 4K one:

And their 1080p one:

Rather handily, there are little instructions on the dongle to tell you which end is which.

The important thing to note is that they are both "plug and play", no drivers needed.

The main difference between the cables is that the lower-resolution one has a locking latch on the DisplayPort end.

I just couldn't get the lower-resolution one to work. My laptop saw it, it identified the monitor and its available resolutions, my sound output could be routed to it - but no video appeared. Yes, I tried rebooting and updating, and unplugging, and sacrificing a chicken - no dice.

The other one worked perfectly. Video came through crisp and clear. Instant detection. Like any modern electronics, it did get a little warm with constant use - but nothing too serious.

Bonus Flipmo Selekta!

What if you want to go the other way? Converting HDMI to DP? Let's go!

Wait? Why is there a USB plug on this thing?

The standard DisplayPort can supply 3.3V @ 0.5A. That's usually enough to power a converter chip. However HDMI can only do 5V @ 0.05A which is insufficient to power anything useful⁰.

Does it work? Yes! The USB plug is only used for power - it doesn't require any drivers or configuration. Plug it into your laptop or hub, plug the HDMI jack into your port, run a DisplayPort cable from it to your monitor. Done.

Buy

Please click the affiliate links so that I can feed my crippling technology addiction.

• DisplayPort to HDMI (HD & latching)
• DisplayPort to HDMI (4K non-latching)
• HDMI to DisplayPort adapter

But is it any good? No. Not really.

Hardware

It's a fairly chunky hub, with a tragically short USB cable.

The USB cable has a dongle which converts it from C to A. That's handy if you don't have enough C ports. But the cable being so short means it is sort of awkward to place. If you're on a narrow desk, the weighty adapter will just be left swinging.

On the back are four ports - two DisplayPorts and two HDMI.

But you can only use two at a time. I stuck a DP in the left and an HDMI in the right and (eventually) it worked! I was able to get 4k @ 60Hz and 1080p @ 60Hz on my screens.

It also passed through audio, although I couldn't find a way to select which monitor received the output.

There's also the requisite blue LED to let you know it is working.

Sadly, it is a bit of a faff to get set up because it is a DisplayLink adapter, rather than a USB-C hub. The manual spends 11 pages talking about driver installation!

Linux

Plugging it in to Linux shows 17e9:6000 DisplayLink USB3.0 5K Graphic Adapter - so it was detected without issue. That said, there were some warnings in dmesg:

Warning! Unlikely big volume range (=672), cval->res is probably wrong.
[7] FU [USB Audio Playback Volume] ch = 6, val = -10752/0/16

But plugging it in doesn't give you extra screens. Instead, you need to visit DisplayLink.com to download the drivers. They are only available for Ubuntu Linux. There are also drivers for Windows, ChromeOS, Mac, and Android.

Despite my best efforts, I couldn't get them to work. It looks pretty buggy. Instead, I downloaded a random GitHub repo which installed the right drivers and got it working.

Once that was done, my laptop happily detected both external screens - one HDMI, one DisplayPort. It was able to change resolution, rotation, and refresh rate using Wayland. It even worked through the USB-A socket as well as the C.

Verdict

It's hard to know who this adapter is for. On the one hand, it does its job brilliantly. It turns your USB3 / USB-C port into a dual output device for two 4k monitors. On the other hand, that's all it does.

It costs £80 - which is a large chunk of change. Especially considering you can get USB-C hubs with dual DisplayPort for literally half that price - and most of those also come with extra USB ports, Power Delivery, Ethernet, audio etc.

Installing the DisplayLink software is a pain. USB-C means that I should be able to plug in an adapter and have it just work. With this, you have to manually install drivers and reboot before it will work. Good luck getting those drivers installed on a corporate laptop!

In theory, it can go up to 5K (5120x1440) on each DisplayPort - but I don't had a screen to test it on. If you need that sort of resolution, that's the only reason I can think for buying this.

It works - but it isn't plug-and-play, the drivers are a pain, USB cable is too short, it has limited functionality, it is too bulky, and is over-priced.