I have a 450W PSU, and the box and sticker show that it has 19A on the 12v rail. What is the minimum requirement for the GT 640 GDDR5, and will I be able to run it? I had shortlisted this card along with the GTX 650 (Non-Ti) due to various reasons. First, my PC is like 7 years old, and I'm not gonna build another one until next year, that is after I finish college. Second, here in India the prices are wild. The GTX 650 Ti is like $200+. So only these two cards, and I'm given to understand that there isn't a whole lot of difference in performance with these two.