Does using a KVM switch add input/display lag?

[BareKnuckleRoo]

My upstairs setup's getting moved around a bit to accommodate some other furniture, and as a result two computers are going to be setup together on one desk with a KVM switch. I'm currently a bit restricted as far as computer space goes, so sharing a desk is the easiest way to set things up. The only issue is that my gaming rig is going to be on the KLM, and I've only just now worried about possible input or display lag when playing shmups if everything has to go through the KLM.

Do I have to worry about input lag? I guess I can plug in a controller or another keyboard to bypass the KLM if this is the case. Will it add any extra frames of monitor lag? I can't see any way around this other than finding an alternative setup if this is the case.

[matrigs]

No.

I'm not sure if this will help you out in your specific situation, but in case you have separate monitors for both computers and just want to share a mouse and keyboard you can check this out:

http://synergy-foss.org/

[BareKnuckleRoo]

We actually used to use Synergy when we had a Mac and PC together, very handy, but the desk for the PC now only has space for one monitor.