The Advantages of DisplayPort vs. HDMI on PCs?
DisplayPort Features for PC Users
While rather long HDMI cables are commonly available, the HDMI spec doesn’t cover how good they have to be at what length. The signal can therefore fall off dramatically as you get to and beyond 15 meters (about 50’).
The DisplayPort standard calls for 15m cables that can provide HDTV video at full quality. It is lower than DisplayPort’s maximum capabilities, but a big help if you want to hook up a PC that is in your living room - but not a dedicated HTPC - to your home theatre.
Longer runs, such as between rooms (up to 100m’), will need signal boosters or extenders. Where is FireWire over Cat5e/Cat6? Without the $300 converters at each end? …now that would do the trick for long runs.
Still to Come
The potential advantages of DisplayPort have less to do with the cable and connector than the associated technologies. The most significant difference between HDMI and DisplayPort is that the latter leaves behind the LVDS standard in the monitor. This enables what they are calling Direct Drive Monitors.
A monitor generally requires LVDS (Low Voltage Differential Signaling) circuitry to interpret and use the signals it gets from source devices. A Direct Drive Monitor could run from the DisplayPort signal without that circuitry. This means thinner and lighter screens that draw less power for laptop users.
Other features are also based around pretty radical differences with HDMI. DisplayPort sends data in packets, and could therefore be used to transfer signals other than audio and video. One suggested use is to avoid having a separate cable for the webcam and mic of a monitor that has those built in. Another nice possibility is if the DisplayPort included on Apple’s LED Cinema Display could also carry the data from the USB hub. Sure they have that MagSafe cable, but you still need to plug in the USB separately at the laptop end. There goes your only USB port if you are using an Air.
The DisplayPort could have you sit down with your fancy laptop in front of your fancy screen, plug in one thing (two if you’ll be there awhile and want to charge your battery), and you can sit back to work, or play, right away. All of this is great, but all of it is also theory. None of it is available, or even promised, to the consumer. All the aforementioned goodies are possible - none are certain.
HDMI and DisplayPort: Compatible?
DisplayPort can carry a DVI/HDMI video signal with an adaptor (under 15 USD). While that doesn’t make it preferable, it does make it less unattractive. Note that, as we’ve been mentioning, there is a significant difference between DVI/HDMI and DisplayPort signals.
While the cable may be able to carry the signal, the hardware might not be able to output or interpret DVI signals. This isn’t a problem for now. Since DVI/HDMI is so prevalent, not including, at least, the possibility of support via an adaptor would be a serious flaw.
But, if DisplayPort gains popularity: you may see some manufacturers skimp on supporting DVI signal output. Devices capable of outputting both signals are referred to as “multi-mode” on the DisplayPort website.
HDMI and DisplayPort: Complements or Competitors?
The thing is: DisplayPort doesn’t really want to go head to head with HDMI. The potential advantages it offers are all on the computing side. The home theatre user has little to gain. A thinner monitor that saves a couple watts an hour is definitely a bigger deal to a laptop buyer than someone picking out a six foot wide television.
The only existing advantage, cable length, is again more of a PC consideration than a home theatre one. A PC 30-50’ from a stereo or TV is common. Lengths like those within a home theatre itself aren’t that common.
Finally: would a home theatre user rather have the, as of yet unrealized, functionality to also hook up a keyboard, mouse and web-cam; or HDMI’s existing, and improving, Consumer Electronic Controls, which allow signals from a remote control to move from HDMI connected devices to one another?
DisplayPort’s marketing spins this by saying that HDMI and DisplayPort are complements, not competitors. The argument they make is that HDMI is not meant for computer equipment. It’s meant for home theatres, while DisplayPort is meant for PCs. This begs the question: what happened to home theatre and PC integration, let alone purpose built HTPCs?
Computers In More Places vs Computers Everywhere
If a good job is done implementing DisplayPort’s computing advantages (fewer cables and thinner/lighter/lower power monitors): PC users, laptop fans in particular – not just manufacturers - actually stand to benefit. Most home theatre users will continue to be better off with HDMI.
The problem is that the computing industry has been pushing the “computers everywhere” concept. Having computers everywhere, or moving towards this, requires two things: mobility and integration. DisplayPort might succeed in improving the first if they can improve laptop monitors.
By introducing a new connector as a “complement” to HDMI, and pushing for the different connectors to be used for PCs and Consumer Electronics respectively, they level a powerful blow against integration.
Laptops outsell desktops, so giving them the nod makes sense. HTPC users, or those wanting to use PCs or PC monitors with a home theatre, get to pick up the slack - and not just that from the extra length of the adapter. Getting your computer to turn on and play using the remote for the home theatre, and vice-versa, isn’t going to be as easy, if even possible.
What Should I Buy?
If we don’t see the new Direct Drive monitors and other benefits touted about DisplayPort, everyone is getting taken for a ride. Until the proposed advantages are actually available, HDMI remains the port of choice. If it doesn’t cost anything more to get both, then go ahead. But if you can only have one, make it HDMI.
This post is part of the series: Next-Gen PC Cables
USB, eSATA, and FireWire are all getting makeovers on the storage side, and Dell wants you to use DisplayPort instead of DVI or HDMI. The latter’s Type-B connector could give it a huge boost though.
