Unfortunately, the Montech X3 does not have controllable RGB fans, they only turn on or turn off. If you would like to control the fans, you would need to upgrade and replace them.
Its been some time since this post but, If you are having issues with the fans running besides RGB lighting, I believe the montech cases come with Molex connector fans, you will need to plug your power supplies molex power cable into the case fans daisy chain of molex connectors. Let us know what you run into!
Submit photos and a description of your PC to our build showcase
See other custom PC builds and get some ideas for what can be done
Services starting at $149.99