Mate.. RGB are a different kettle of fish.. each has 3 LED inside.. 1 red 1green 1 blue.. these 3 are interconnected so you can bring the red up slightly, the green more.. skip blue etc. Having all these 3 working together like this can give a choice of over 1 billion colours.. cheaper RGB less colours.
The PWM to drive these needs to show a colour differentiation that is as smooth as silk.. no jumping between colours.
Then take in wether they are 3528 LED..50/50..50/60 etc.. each draw different current.. each have a different light output.
When you buy RGB it pays to buy quality as the cheaper models tend to " lock on" and so one will always have red active etc and it throws the whole colour spectrum out and looks shit
