I don't know whether this is relevant. I have an XP machine and W7 64 bit machine. I had a lot of problems with KVM switches (mouse and keyboard stopped working after some time) - the 3rd switch resolved most of them. The remaining problem is that unless the xp machine is switched through on boot, the screen resolution is completely screwed up and cannot be corrected. If It's switched through on boot the resolution is fine. The W7 machine is fine either way.