The OCZ StealthXStream 600 Watt has four 12v rails rated at 18 Amps each... and the 260 asks for 36 amps on the 12v rail. I don't know quite enough about power supplies to know whether the four 12V rail ratings at 18 amps each "satisfies" this requirement.
you should be fine. You can always email OCZ and ask them. Give them the full system spec. I had the same problem with an old PSU. It looked all ok but there was something odd inside so i went for a Corsair Powersupply 620W
Thanks for the help guys. System is up and running now, working like a dream. Thanks!