Gadget Review: DisplayPort to HDMI Showdown
From crummy old S-Video, through SCART, VGA, and HDMI - the world of video connectors has never been entirely cross compatible. Oh, sure, with enough boxes and adapters you can usually get an old device to talk to a new one. But results are never guaranteed and quality can take a hit.
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.
| Feature | Regular | 4K |
|---|---|---|
| Max resolution | 1080p | 4K |
| Max refresh | 60Hz | 60Hz (4K)
120Hz (2K) |
| Features | Latch on DisplayPort | Nylon braided cable |
| Cost | £10 | £12 |
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
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- DisplayPort to HDMI (HD & latching)
- DisplayPort to HDMI (4K non-latching)
- HDMI to DisplayPort adapter
-
HDMI 2.1b will support higher power - but those are pretty rare. So a USB plug is needed to power the converter. ↩︎
@Edent Must admit, I have struggled to see the need for DisplayPort on the grounds that HDMI seems to work okay.
(Although I freely admit that my opinion is partly due to previously working in an office where there were a mix monitors of both types, a shortage of one of the cables and senior management (whose technical proficiency lay elsewhere) expecting a multi monitor solution to appear on their desk as if by magic.)
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Dave Cridland says:
The biggest advantage of DisplayPort is that it's royalty-free, unlike HDMI. This is visible in (for example) what the open-source AMD drivers on Linux will support.
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