Even know this is a dated thread, I didn't see anyone in this thread confirm whether or not the 3D has a 4G radio, proof inside this link and attached picture...
YouTube - CTIA 2011: Sprint HTC EVO 3D Hands-On Demo
It's a specific part in time from the video in this other thread from freeza...
http://forum.ppcgeeks.com/htc-evo-3d...eo-evo-3d.html