If you see your +12V1 and +12V2 separately do not meet the minimum requirements of your GPU you want to buy.
I never bought raidmax either way, I read too many bad reviews on them and it made me look the other way. I have been with corsairs PSU since the very beginning. My first PSU (500 watt PSU lasted me 7 years until I upgraded my GPU).
You can easily purchase the 750 watt psu if you like but you dont need 750watt psu for that, but for $10 bucks, why not, its good for the future. Either the 600 watt or 750 watt choice is perfect for you.
Yeah my only uncertainty was about how the 12v rails acted on that PSU. Ill probably end up getting a Corsair or EVGA PSU. I love corsair my case is a carbide 400r. That PSU is one year old and when i put my computer together i did go with a cheap one everything else in my computer is quality except that.
Yeah cant go with the "cheap" brand on computers.. you will be asking for problems. Corsair makes very good PSUs cant speak for EVGAs PSUs but do what you feel is right but I believe you need to change your PSU out, sell the current one to get a personal rebate on your new PSU.