My monitors have DVI and HDMI inputs so I connect each computer to each monitor using the HDMI/DVI outputs of my video cards. Then just switch the inputs on the monitors for computer A or B.

@Former user - Your well-meant feedback is that my KVM Switch has both HDMI/DVI options? Is that it? Or are you suggesting an alternative?

DVI = hdmi with no audio. This simplifies it a bit, but it is true for the most part.

@fr0sty - Yes of course, no audio. What’s “the most part” mean for me?

Sorry if my post was confusing. My KVM switch does not have HDMI/DVI so I use it only to switch keyboard/mouse, and I switch the inputs of each monitor to the corresponding computer. I was offering it as an alternative if your KVM switch does not support HDMI/DVI

If your computer video boards and monitor all support hdmi, stick with that for your kvm switch. The one I use is just a little over $100 and supports 4k60p. There's also a cheaper 4k30p model. If your monitor is strictly vga, a vga kvm will work with simple passive hdmi-to-vga adapter on the computer hdmi output which is fine for resolutions up to 1080p as long as you don't expect to play audio through your monitor. Most new monitors don't have vga ports any more. To use one with a computer video board that is strictly vga, converting vga-to-hdmi from a video board requires an active adapter that's more expensive, will also require power (usually usb), and an audio feed (usually from the computer's headphone jack)... probably swapping the video board out for an inexpensive one supporting hdmi would be simpler all around. The newer hdmi kvm switches are great, support keyboard hot-keys for switching keyboard/video/mouse, are implemented with a combo hdmi/usb cable for each computer, and usually support switching a usb port for sharing a usb printer.