Well, one of the problems of having a general purpose processor do the job is that it's not configured for the job, thus the expensive calculation cost. In other words, you're modifying a software FIR and having the processor do the calculations. All the math has to be done without special hardware acceleration. A digital signal processor, on the other hand, is specially designed to do FIR and IIR calculations and can do them quite efficiently, typically at the hardware level. The TACT and others that use DSPs therefore have an advantage in terms of processing speed. But I don't think that I would be turned off by the processing power required for these calculations for a general purpose computer, as I'd probably use a single computer just for doing the calculations and maybe serving music. Other than that, and the computer might not be able to keep up, but it shouldn't matter much. My bigger worry would be getting the sound of the fans low enough -- I can hear the sound from the fans of my cheap home computer across the house, if the computer room's door is left open. It's obscene, but a nice power supply and nice fan is more than what I paid for the entire computer system, so it's not worth it right now for me to upgrade it.
