Hey, basically I'm upgrading from a gtx 660 to a R9 380 and was wondering if I needed a bigger psu? I have an i3 6100, 8gb of ddr4 2666mhz ram, 120gb samsung ssd evo, 1tb western digital 7200 rpm drive and a dvd drive/3 case fans. MSI themselves recommend a 500w and PSU calculators I have used...