KVM switch video problem

Is it a hardware switch or software?

I have a crappy old rotary-switch job that works fine, except if the switch is right on the connection - then it gives me difference colours and fading.

If your switch is a flash push button software-based thing, then you may need a better one. I would expect a hardware one to be fine.

You have all the cables seated correctly?

robo.

Have also found that buying better VGA cable to go from the PC's to the switch can fix this problem.

The standard cables are quite thin.

The SVGA cables are like the cable coming from the monitor, quite thick and better shielding.