just because the plugs are red,green, and blue doesn't mean it's RGB.
that is most definitely Ypbpr also known as "Component" video
great if your TV has analog "YpBpr" analog input. not so great if you have a similarly color schemed and named "YCbCr" also known as "digital component video." check your TV manual to find out if it's cross compatible or one or the other.
if you are looking for RGB ... VGA already is RGB. you just need to break out the signals from the cable.