Command response time is TOO LATE! Makes games unplayable.

I've been playing emulators for a long time and I just recently downloaded Nestopia and Fusion. But it seems that there's a noticeable and pesky lag for input response. Like in ninja
gaiden for nestopia, if I try to jump off of a ledge at an exact moment I'll die most of the time, because the emulator won't recognize my command input until 1/10 or 1/5 of a second after I press jump.
This is true for both keyboard input as well as controller input. How can I fix this?

This is sort of the of those annoying questions. Rightly so for the OP as well... If you're using USB there really cant be any lag. The usb will time out before the human brain can respond. Sounds to me like an emulator issue but I would be shocked to here top emulators like Nestopia and Fusion have issues. I would guess the lag is do to something in the way, like spy ware.

INFO: 1/10 of a second is 100 milliseconds. The usb device will give up after a few milliseconds so its not your controller ( if its usb ).

The best way to fix an issue like this is to have two computers ( one without the issue). I realize this does not help much but its one of the questions that dont have immediate answers.