HDMI, DisplayPort or VGA: which cable for which screen

Most display problems are a connector question rather than a hardware fault, and the choice affects resolution, refresh rate and whether sound travels with the picture.

VGA

Analogue, and the oldest of the three. It still works for basic office resolutions but softens noticeably at Full HD and carries no audio. Fine on older machines, not worth choosing for a new one.

HDMI

Digital, carries picture and sound on one cable, and is on virtually everything. The version matters: older revisions cap what they can drive at higher resolutions and refresh rates.

DisplayPort

Generally the better choice on a computer. It supports higher refresh rates at a given resolution and can drive several monitors from one port on machines that support it.

When the cable is the fault

Flicker, black frames or a screen that refuses its full resolution are often a cheap or over-long cable rather than a failing monitor. Swapping the cable is the cheapest diagnostic step and worth doing first.