My DeepCool cooler comes with standard RGB. The RGB connector is a 4 pin connector, How do I get it to work with a 3 pin ARGB header? The cooler is advertised to be Aura Sync compatible.

There is a significant difference between the way ARGB and RGB technologies function. ARGB utilizes 3 out of the 4 pins, and is pinned as +5v, Data, empty, and Ground. Standard RGB uses all 4 pins, and is pinned as +12v, Green, Red, and Blue; where each of the 3 last pins control the amount of the corresponding color that is to be displayed at any given time. Aura Sync is a lighting software suite from Asus that can control both ARGB and standard RGB, but you would need the proper interface to control the respective technology.