Buying a DisplayPort cable

Transmission speed

All DisplayPort cables support the same features. The primary difference between them is transmission speed. Resolution, color depth, number of monitors and refresh rate are all dependent on how much data the cable can transmit.

Updates to the DisplayPort standard typically include a boost in transmission speed (also referred to as bandwidth). To make it easier to find the cable you need, the VESA DisplayPort Task Group gives transmission speed a name.

Cable length

Passive cables transmit signals. That's all they do. The longer the cable or the more data (higher resolution) you try to push through it, the more likely the signal will weaken and suffer from errors and interference.

The maximum length of a passive DisplayPort cable is at least 15 meters/33 feet. Depending on the quality of the cable and other factors, you may be able to transmit video and audio over greater distances.

Passive vs. active cables

If you need greater distance, you have two choices: a signal booster or an active cable. Both do essentially the same thing. They regenerate or increase the strength of the signal so it can be transmitted further. Depending on the resolution, active cables can easily reach 150-ft or more.

Choosing a DisplayPort cable FAQ

What is Display Stream Compression (DSC)?

High resolutions of 8K and beyond, greater color depths and increasing frame rates push the limits of video cables, even high bandwidth cables like DisplayPort. The only way to transmit more bits is to add more lanes to the cable or compress the signal. Display Stream Compression (DSC) is a new standard first introduced in DisplayPort 1.4 that enables visually lossless compression of 2:1 or 3:1. This "light compression" allows video to be encoded and decoded in real time with very low latency, making it ideal for high performance applications like gaming. Compared to video transmission without compression, DSC saves power and can allows for resolutions up to 16K (15360 x 8460). However, for the best image quality, it is best to avoid compression of any kind.

How do I check my DisplayPort version?

Graphics cards and port drivers do not usually indicate the version of DisplayPort they support but they will show maximum resolution and refresh rate (e.g. 4096 x 2304 @ 60 Hz). Identify the processor used by your computer, then refer to the graphics specifications on the manufacturer's website.

What is Dual-Mode DisplayPort?

Devices that support DisplayPort Dual-Mode will detect when an HDMI and DVI Single-Link monitors is connected and will send HDMI/DVI signals instead of DisplayPort. It is an optional feature that some device manufacturers implement but it is not required. How do you know if your laptop or dock supports DisplayPort Dual-Mode? The port is sometimes labeled with the DP++ logo but not always. Refer to the documentation that came with your device.

DisplayPort vs HDMI. What's the difference?

DisplayPort and HDMI are often compared because they have many of the same features. Aside from the fact that DP and HDMI use different connectors, DisplayPort has more of a computer focus whereas HDMI has become the de facto standard for connecting televisions and consumer AV products. By virtue of its higher bandwidth, DisplayPort supports higher display resolutions and refresh rates, making it a popular choice for gamers and professional video editors.

Does DisplayPort support audio?

Yes, DisplayPort can carry multi-channel digital audio and video signals simultaneously although it isn't always implemented by device manufacturers. If DP audio is supported by your PC graphics card or laptop, you will be able to stream audio to speakers built into your monitor or connect speakers to your monitor instead of your computer.

Evolution of the DisplayPort standard

With each update of the DisplayPort standard, more bandwidth is required to support higher video resolutions, refresh rates and color depths. The effective data rate of DP 1.3 and 1.4 is sufficient to support a 4K, 24-bit color monitor at a refresh rate of up to 120 Hz, but it is not able to support the new generation of higher resolution 6K and 8K displays without resorting to compression.

What is a color space?

A color space is a defined range of colors that can be represented in an image. The two primary color spaces used to represent digital video are RGB and YCbCr. Two important characteristics of a color space are Color Depth and Gamut. Color Depth is the number of bits used to represent the color of a single pixel and determines the amount of shading or gradation. Gamut refers to the number of colors available.

The initial HDMI specification provided support for 24-bit Color Depth (8-bits per color x 3 colors RGB). HDMI 1.3 introduced Deep Color, which added support for 30-bit, 36-bit and 48-bit color depths. It's worth keeping in mind that the human eye can only distinguish around 10 million different color, so 24-bit color is adequate for most situations.

What is chroma subsampling?

Chroma subsampling is a form of video data compression. It reduces the amount of color data in a video signal in such a way that there is little or no visible impact on image quality.

Each pixel in a video image includes information on brightness (luma) and color (chroma). Since human eyes are more sensitive to differences in brightness than color, chroma subsampling reduces the amount of data transmitted by allowing pixels to share color data with adjacent pixels.

Chroma subsampling is represented as three digits. The first number is the number of pixels in each row of the sample. The second number indicates the number of pixels in the TOP row that have color information. The third number indicates the number of pixels in the BOTTOM row that have color information.

• 4:4:4 means no subsampling. Each pixel has its own color information.
• 4:2:2 indicates that two adjacent pixels on each row share color information, representing a 50% reduction in color data.
• 4:2:0 means the bottom row has no color information and uses the information provided for the top row. This approach reduces the color data by 75%.

DisplayPort 2.0 monitor configurations

With the greater bandwidth of DP 2.0, it is possible to connect two 4K monitors running at 144 Hz using a single cable and no compression. This should be good news for gamers and virtual reality (VR) enthusiasts, who look for ultra-high resolutions and refresh rates.

The tables below illustrate the versatility of the latest DP standard.

Transmitting DisplayPort signals

DisplayPort cable length

According to VESA, the maximum length of a DisplayPort cable is 15 meters (49 feet) but distances of over 15 m are possible depending on resolution. A 15 m cable like Eaton's P580-050 can transmit a DP signal at 1080p. A good practical approach is to test transmission over the required distance with a good quality cable. If you see problems in the strength of the signal (e.g. sparkles or other artifacts), add a signal booster like Eaton's B121-000.

DisplayPort extenders

When transmission distance requirements exceed the limits of passive and active cables, it's time to consider the various forms of signal extension.

DisplayPort over CATx

A DP over CATx extender will convert the DisplayPort signal into a proprietary form that can be transmitted over the category cable and reconverted at the other end with no loss of signal strength or fidelity. Using this approach, a DisplayPort signal can be transmitted about three times further than an active DisplayPort cable–approximately 100 meters (328 ft.). Shielded (STP) Cat6 cable is recommended for its ability to reduce EMI interference from power lines and crosstalk within the cable.

DisplayPort over Fiber (active optic cable)

The connectors on fiber DisplayPort convert conventional electrical inputs to pulses of light that are transmitted at high speed through optical fiber, then converted back to electricity on the receiving end. Since signal transmission is optical, it isn't subject to EMI/RFI line noise. Fiber DisplayPort is subject to the same 100 meter/328-foot limitation as copper Ethernet cable.

Wireless DisplayPort extenders

A hardwired extender uses an Ethernet or Active Optical Cable to pass data between a transmitter and receiver. A wireless extender sends the DisplayPort signal using one of the WiFi protocols (e.g. 802.11ac or 802.11n). Wireless is generally slower than hardwire so make sure the video resolution and frequency is sufficient for your needs. For example, Eaton's B126-1D1-WHD1 can extend a 4K/30 Hz signal up to 98-ft.

For more on DisplayPort Video Extenders and how they work, see our Video Extenders Technology page.

Switching and splitting DisplayPort signals

Switches and splitters are often confused and for good reason. They perform similar functions. A switch takes multiple inputs and lets you choose which one to display on your TV or computer monitor. A splitter does exactly the opposite. It takes a single video signal and replicates it to multiple displays.