I guess it depends on what fans you're running, but 1 A should be enough for at least 3 of the most commonly used ones. Noctua lists max input current for all

I guess it depends on what fans you're running, but 1 A should be enough for at least 3 of the most commonly used ones. Noctua lists max input current for all their fans, and even the high speed industrial ones are only 0.18 A.