PostmanPot
Honorary Master
It provides 40A on 12V, The 570 uses 35A (recommended 38A).... then if he overclocks like he wants to he's going to be using a tad more wattage. I know the Corsair psu's can push out a lot of juice (my old Corsair VX450 maxed out at 600W) but it's probably better to be safe.
Those amp requirements are so that the gfx manufacturers cover themselves from cheap/junk PSUs that lie about wattage they deliver. GTX570 uses no where near 38A.
CX500 is enough with OC. I don't believe there are grounds to start bringing up "safer to go with x..." etc.