Stuck with A4 size in revtex and how I solved it

I was setting up Miktex 2.9 on my new laptop, and revtex just couldn't output any other paper size than A4 when the setting was clearly changed. I then decided to see whether the documentclass[...]{revtex4} had something to do with it, and I was happy to find that by changing it to {revtex4-1} solved the problem.