I cant comment just on the Tri-X but i do own R9 290 VaporX cards..
When not under load you basically cant hear them (with IFC on), under load you can hear the card (but doesn't even come close to the Gigabyte Windforce R9 290 I had my hands on for a bit).
The VaporX does run cooler than just the Tri-X, has binned chip, custom PCB, backplate (the card is pretty heavy and needs it) and power delivery and the cards i have overclock like a boss. I can definitely recommend the VaporX.
Thing to note is that the VaporX card takes up about 2.5 slots on your mother board and you may also have trouble mounting stuff above the card as well due to the backplate... but it think its worth it