I don't believe that THC is working yet in mach4, so that would probably point you to Mach3, right? Supposedly the latest beta runs pretty well, but it's only been out a few days. But, if you need THC, it may be a while. I don't know much about plasma, but I believe that all current THC boards compatible with Mach3 use a parallel port, and Mach4 does NOT support parallel ports. Does this help? Might be best to email Art with this question.