KVM switch resolution is often overlooked when researching KVM switches. Some video applications run at very high resolutions, sometimes with digital video, and other times people are running very low resolutions such as 800 x 600. KVM switch resolution is an important spec of whatever KVM switch you choose, so that you are able to push the high bandwidth video through the switch if you need to.
If you get an out of range signal on your monitor, whether through KVM switch hardware or whether directly attached, it is usually a resolution issue. If it is out of range usually the frequency is too high caused by a resolution that the monitor is incapable of. The higher the resolution, the higher the bandwidth, and if you are pushing too much information to the monitor, it will not be able to handle the video.
So KVM Switch resolution is definitely an important spec to take note of while searching for a KVM switch, and if you get stuck with a switch that can't handle your video you will be upset. The KVM switch resolution is usually detailed in the manual, so proper research will save you trouble down the road with hardware that doesn't suit your needs.