ARGB stands for addressable RGB, which means every LED in the fan can be set to a different colour at the same time. That is what makes rainbow waves, chasing patterns and colour gradients possible, where plain RGB fans can only display one colour across the whole fan at once.

The two are electrically different and not interchangeable. ARGB uses a 3-pin 5V header on the motherboard, while older RGB uses a 4-pin 12V header. The connectors look similar enough to force together, and connecting an ARGB fan to a 12V header will destroy its LEDs immediately, so always check the header voltage before plugging anything in.

Lighting is only half of a fan though. Airflow, static pressure and noise are what actually keep the machine cool, so choose the fan on its cooling specification first and treat the lighting as the reason to pick between two that both perform.