you do realize your talking about a 670...and ONE monitor...only 1080p...that will ultra EVERYTHING and no not less on the psu thats a horrible idea.
Its a decent MID range card (670)... I sell them in my shops...
If it could Ultra everything with everything turned on , why would they sell 680s, or 690s ?
And ANY decent make 500 psu will be fine for a single graphics card.... even my 7990 only uses an 850 OCZ...
All the best Brett