Kinect, Processing, Arduino, and a whole lot of lag

Well, the good news is that I have a tracking program that, when a point is at a certain depth, communicates with an Arduino through processing and turns on an LED. That's exciting. What isn't exciting is the huge amount of lag I'm dealing with. From troubleshooting and writing out various sections of code, I've determined that the lag is a result of the communication between processing and Arduino and not as a result of any of the actual program content, as little lag is present when the Arduino communication is stripped from the code. I'm using a library called "Firmata" as a means of communicating with the Arduino. It involves loading an unchanging Firmata code onto the Arduino and then using a Firmata library to actually control the Arduino through code in Processing. It's very cool. It is, however, also a very big source of lag for some reason. I previously tried communicating with the Arduino by sending communication between Processing and the Arduino coding interface using serial commands, but this also created lag. I hoped using Firmata would fix the problem, but it just really hasn't at all. It's a problem I'm still looking into and one that, unfortunately, makes my program pretty much useless for the moment.