How to Choose a DisplayPort Cable, and Not Get a Bad One!

DisplayPort makes display cable selection pretty easy.  A standard DisplayPort cable is designed to work with any DisplayPort Source device, such as a PC or laptop, and any DisplayPort monitor.  This means that a standard DisplayPort cable will work with the very first DisplayPort systems and displays introduced around five years ago, and they will continue to work with the newest and future systems and displays that support multi-stream and display resolutions up to 4K (Ultra HD) at 60Hz.  You can also use a standard DisplayPort cable between a PC and a multi-stream hub, or between daisy-chainable multi-stream monitors.  You don’t need worry about getting a special cable to support certain DisplayPort capabilities.

However, we should note that there is one rare exception to this rule; there are a few Reduced Bit Rate (RBR) cables on the market that will support only up to 1080p, but these are generally restricted to projector installation applications. Unless the cable is identified as RBR, it is a standard DisplayPort cable and will support all DisplayPort configurations.

Despite what you may read, there is no such thing as a DisplayPort 1.1 cable and DisplayPort 1.2 cable.  A standard DisplayPort cable, including the so-call DisplayPort 1.1 cables, will work for any DisplayPort configuration including the new capabilities enabled by DisplayPort 1.2, including 4K and multi-stream capabilities.  All standard DisplayPort cables support RBR, HBR (High Bit Rate), and HBR2 (High Bit Rate 2), which can support 4K at 60Hz, or up to four 1080p displays using multi-stream.

While retailers may try to sell you a more expensive cable touting it will provide a better picture quality, we are here to debunk that myth. Contrary to what you may think, the more expensive cable will not give you a better picture quality.  DisplayPort uses packetized data, similar to USB and Ethernet, to send digital display and audio data, therefore you either get all of the data or you don’t.  Unlike other older video interfaces, you don’t get a “better” picture or other incremental improvements with a more expensive cable.  But of course a poor quality cable could lead to data errors and obvious corruption of the video or audio data, but you can avoid such cables, as explained further below.

One thing you will need to consider in your cable purchase is the connector type on each end of the cable.  There are two DisplayPort connector types.  The standard DisplayPort connector (see image 1) is about the size of a USB connector, and this type is commonly used on DisplayPort-enabled PC monitors.  The smaller mini DisplayPort connector (see image 2) is commonly used for the DisplayPort output on notebook PCs including Apple products.  The mini DP connector is now also used for Thunderbolt that is widely used on Apple products.  And you can connect any DisplayPort monitor to a Thunderbolt Source, using a standard DisplayPort cable, while achieving DisplayPort quality (Thunderbolt is backwards compatible with DisplayPort, and even includes support for Dual-Mode DP-to-HDMI and DP-to-DVI adaptors, and DP-to-VGA adaptors).

Image 1

Image 1: Standard DisplayPort Connector

Mini DisplayPort Connector

Image 2: Mini DisplayPort Connector

An important criterion for selecting a DisplayPort cable is to know which type of DisplayPort connector you need at each end.  The other obvious criterion is cable length; they are generally available in lengths of 1 to 3 meters (up to about 10 feet).

As mentioned previously, it is important to avoid low quality DisplayPort cables to prevent unexpected video or audio problems, and sometimes even system power-up problems.  Always buy cables from a reputable computer system or accessory brand.  Or safer yet, buy a cable that is DisplayPort certified.  DisplayPort certified cables are listed here.

Recently VESA has experienced quite a few complaints regarding troublesome DisplayPort operation that ended up being caused by improperly made DisplayPort cables.  These “bad” DisplayPort cables are generally limited to non-DisplayPort certified cables, or off-brand cables.  To further investigate this trend in the DisplayPort cable market, VESA purchased a number of non-certified, off-brand cables and found that an alarmingly high number of these were configured improperly and would likely not support all system configurations.  None of these cables would have passed the DisplayPort certification test, moreover some of these cables could potentially damage a PC, laptop, or monitor.  We have not seen problems with the cables supplied by major computer brands, or major computer accessory brands, nor have we seen any problems with any of the cables that have been DisplayPort certified.

We expect to be adding more certified cables to our published list in the future and will continue to encourage DisplayPort product certification. To achieve the best of DisplayPort’s capabilities, we highly recommend using DisplayPort certified cables, or those from major brand names. Please continue to send us any questions or reports of bad cables that you may be experiencing.

— Craig Wiley, Chairman, VESA