4K or UltraHD Displays and Your PC

4K computer displays require hefty hardware upgrades

ASUS PA328Q 32-inch 4K UIltraHD PC Display
ASUS PA328Q 4K Display.

Photo from Amazon

4K, or UltraHD (UHD) as it is also known, refers to a class of super high definition displays and video. The "4K" is a reference to the horizontal resolution of the picture, typically either 3840x2160 or 4096x2160 pixels. This is roughly four times the resolution of the current HD standards that top out at 1920x1080. While 4K computer monitors are becoming commonplace, achieving true UltraHD on any PC requires significant hardware upgrades.

Information in this article applies broadly to a type of computer hardware.

The Limitations of 4K Computer Displays

The availability of 4K UHD computer monitors has lagged behind the television market due to several technical limitations.

Video Bandwidth and Connections on Computers

Computers face a problem rendering 4K or UHD content: The extremely high resolutions require a large amount of bandwidth in order to transmit the increased size of the video data. Older computer video technologies, such as VGA and DVI, lack the bandwidth and therefore can't deliver those resolutions reliably. To maintain 4K resolution, you need newer video connectors such as HDMI, DisplayPort, and Thunderbolt 2 or 3.

HDMI is used by all consumer electronics, which gives it an advantage when it comes to adoption by the computer display market. A video card with an HDMI port is required, as well as HDMI high speed rated cables. Failure to have the right cables can result in lower resolution images.

DisplayPort is used by many computer displays and video cards, though it is less familiar to the average user. The DisplayPort v1.2 specification can run the full 4K UHD video signal up to 4096x2160 at 60 frames per seconds (fps).

Refresh Rate

HDMI signals commonly transmit with a 30Hz refresh rate, or 30 frames per second. This may be acceptable for watching movies on a television, but for computer users, especially gamers, such low frame rates can cause serious eye strain. Gamers prefer 60fps refresh rates or higher for more fluid movement on the screen. The HDMI 2.0 specification corrects this and has become the standard in many PC display cards.

Video Card Performance

Every graphics processor can handle basic video rendering at the 4K UHD resolutions, but fast-paced 3D video games presented in 4K require significant graphics processing power. At four times the resolution of standard high definition, four times the amount of data needs to be processed by the graphics card.

The processing load these cards handle produces significant heat inside a system, which requires greater cooling capabilities. This all comes with a higher price tag. Running multiple monitors with 4K resolutions vastly increases the demands on bandwidth and processing power.

Video CODECs

Streaming and downloading 4K videos presents additional challenges. The increase in the data stream size places a greater burden on internet traffic, and the size of video files has multiplied. Because of this, there is a need for more compact video files that can be transmitted more efficiently.

Most high definition video uses the H.264 video CODEC (short for compressor-decompressor) from the Moving Picture Experts Group, or MPEG. These files are referred to as MPEG4 video files. This has been an efficient means of encoding data, but with 4K UHD video, a Blu-ray disc can hold only one-quarter of the video length. The H.265, or High-Efficiency Video CODEC (HEVC), was developed as a means to resolve this issue by reducing the data sizes.

Older video hardware has been hardcoded to use the H.264 video in order to be as efficient as possible. The same is true for many graphics solutions found in mobile products. Some of the adaptation necessary for 4K can be handled through software, but many older mobile products like smartphones and tablets may not be able to playback the new video format.