is ok 2 corsair ax 1200 i platinum?
that would be my PSU of choice. without having looked at the exact spec, i'd assume that would suffice to power your new Neptune.
It is correct that the Corsair has enough power, but you will have issues if you use it with a Neptune. With the Corsair, you'll need to use the workaround described in KnC's troubleshooting guide, and/or be prepared to tinker!