high-pixel density display environment

The transition to high-density pixel displays that began with smartphones and tablets has spread to the computer monitors. 4K PC screens appeared in 2014, and understanding pixel density has become important when choosing a product, along with screen size and resolution. Our topic is the transition to high pixel density screens, including trends in the latest technology. There are two standards for 4K resolution, “DCI 4K” and “UHD 4K”.

DPI (dots per inch) is the number of dots located within a 1-inch scan or print line. For monitors and displays, DPI is discarded in favor of PPI (pixels per inch). Although PPI is an accurate term for monitors and other displays, the two terms are often used interchangeably.

4K is high-resolution with twice the vertical and horizontal pixels compared to Full HD and refers to resolutions with approximately 4 million horizontal pixels.

 Supports 4096 x 2160 pixels / approx. A 17: 9 screen that surpasses the 3840 x 2160 pixel / 16: 9 (UHD 4K) screen often used on 4K computer screens. Note the difference in horizontal resolution.

At the same time, the 4K screen environment is still in transition, so a few things should be noted, the first of which is the refresh rate issue.

The only interface for 4K screens currently on the market that can display 4K 60Hz is DisplayPort 1.2 which has a bandwidth of 21.6 Gbps. This is because 4K 60 Hz transmission requires a bandwidth of 16 Gbit / s (3840 x 2160 pixels, 32-bit color, 60 Hz). This is well above the bandwidth supported by DisplayPort 1.1 (10.8 Gbps), HDMI 1.4a (10.2 Gbps) and Dual Link DVI (7.4 Gbps). For this reason, it should be noted that currently, when connected via DVI-D or HDMI, the 4K display only works at 30Hz.

However, when it comes to HDMI, the bandwidth of the new HDMI 2.0 standard (HDMI 2.0 level A) has been expanded to 18 Gbps, and new screens have been announced that can display 4K 60Hz with HDMI 2.0 input. As the video output components of the computer (GPU) and other devices begin to support HDMI 2.0, the situation will gradually improve.

In the MST system, the operating system recognizes 4K as a dual screen with a resolution of 1920 x 2160 pixels, so a GPU driver is required to combine the output into a single screen. Depending on the version of the GPU and driver used, there were problems such as syncing the display on the left and right of the screen or a malfunction in a multi-screen environment.

As for the hardware, lately the GPUs already have processing power that could be called excessive for general use, and even PCs that aren’t particularly good should be able to handle the 4K screen (although playing 4K games  on them goes is gonna be a different story)

Support for a high-pixel density display environment in a computer's operating system is called HiDPI support. With operating system support, application support is advancing, and the PC programming environment surrounding HiDPI has moved to a practical level. This encourages the expansion of high pixel density screens such as 4K.