Eternity without a doubt.
Hyperstorm had access to a virtually limitless power source but was limited by how much of that he could bring to bear at any single point in time. He had very limited output in comparison to a cosmic. I saw nothing from him beyond skyfather level.
Thats why someone like Galactus who isnt tapped into any power source and has to rely on outside sustenance could still beat him. Because Galactus operates on higher power levels. Thats why he could just overpower Hyperstorm and turn him into his personal power source.