It is not entirely clear, but I presume you have the option to connect the output of your PC to a display EITHER via HDMI OR via DVI-VGA:
HDMI has a built-in protocol that asks the display what refresh rates (video frequencies) it is capable of displaying. The source (computer) then sends video at a refresh rate that the display can happily use.
DVI-VGA has many variants that, over time, were developed (from having no such protocol, to having a protocol almost similar to HDMI) until HDMI took over as the preferred connection. If a display screen has tearing in the video content, it usually means the source is sending the video at a refresh rate that the display CANNOT happily use. The solution is to manually change the refresh rate in the graphics card settings until the tearing is cured.