Peter Johnson wrote:

I have a monitor connected to my PC using DVI ports on both. But the
monitor has DisplayPort capability. Would there be any advantage in
installing a video card with DisplayPort capability in the PC and
using DP instead of DVI?

DVI and HDMI are the same. Display Port supports higher refresh rates
at the high resolutions.

You didn't mention which brand and model of monitor, or its native
resolution. If the monitor doesn't support higher resolutions and
refresh rates than what DVI/HDMI support then there is no point in
changing your video adapter to something the surpasses what your monitor
can support.

HDMI 1.4: 3820x2160 @ 30Hz
HDMI 2.0: Ups refresh to 60Hz
DVI single-link: 1920x1200 @ 144Hz
DVI dual-link: Ups resolution to 2560x1600
DP 1.2: 3820x2160, 4K, @ 60Hz, 1080p @ 144Hz
DP 1.4: Ups refresh to 4K @ 120Hz and 8K @ 60Hz

Without knowing the specs for the monitor, know way to know what it
supports for max/native resolution and refresh rates, or what
DVI/HDMI/DP specs are supported. Having a DP port doesn't mean the
monitor supports the max DP specs. Getting a video card that supports
higher resolutions at high refresh rates is not going to alter the
hardware in your monitor which might be the limiting factor. However, a
much video card will offer you the opportunity to later improve the
monitor to match the maximums supported by the video card.

https://en.wikipedia.org/wiki/DisplayPort
https://en.wikipedia.org/wiki/Digital_Visual_Interface
https://en.wikipedia.org/wiki/HDMI