72 fans for argb lighting ±
ARGB works almost identical to pwm. You supply enough power to the hub by the molex, it's a constant voltage. Each led (or series of maybe 3 leds) has its own controller chip for the addressing, pwm signal if you like. You are limited only by the strength of that signal, not the amount of fans. RGB is synonymous with a DC fan system, it's amperage controlled by the header, so not powered by external source. Those that are, by large command hubs that are powered are usually limited to @ 6 or 8 fans because of amperage tolerances.
With ARGB, you don't even need hubs, you can use 4way powered splitter, master to 4way powered splitter, master..... And so on, each splitter powering 3 fans, the master carrying the signal to the next splitter. You just need enough power connections to do the job.