i think the neopower is enough, but just enough. i had one and just was not liking were the rails were ( especially the 12v @ 11.7, not that that is low) and i only have one card. plus the dual rail psu's are pretty disbuted as to whether they can be combined or not and so on. personally i would go with something with at least 24amps on the 12v rail, dual gt's are gonna suck a good amount of power. look at the ocz modstream 520 if you like the modular style, or you can go for the powerstream with the adjustable rails which i have and like very much. it is up to you, i dont think the neopower is bad at all and could prob handle it, but to be safe, i would go with more power and maybe not a dual rail (unless you go PC power & cooling sli 510)