ZagiZoveDaGaLove :
Sapphire R9 290 TRI-X 4GB GDDR5 with
Corsair CX Modular Series CX500M, 500 Watt, ATX
No, not even close really. I mean it may work but I would expect shutdowns if you do anything strenuous like game. Consider that OCed that card is capable of peaking at around 500 watts all by itself. Even without any OC at all you're looking at well over 300 watts, almost 400. Contrast that with your PSU which actually puts out around 450ish watts and you can see the problem.
I don't understand, Sapphire clearly states in the system requirments that you need at least a 750 watt PSU. Did you just not believe them or something? You could maybe get away with 600 watts if it were a quality PSU but that series of PSUs is mediocre at best. So yea get a better PSU is the moral of the story.