There are at least two bands with the name RDX:
1.. RDX is a dancehall duo composed of Renegade X and Delomar X, formerly known as Xsytment. They are now considered one of the best reggae shows to watch . in 2012/2013 they have 4 songs in the top 10 of the reggae charts..

Read more about RDX on Last.fm.