In a worldwide ranking for technology and engineering Purdue ranks #45 to OSU’s #64
http://www.timeshighereducation.co.uk/world-university-rankings/2014-15/subject-ranking/subject/engineering-and-IT
Overall, USNews ranks OSU #54 compared to Purdue at #62.
Forbes ranks Purdue at #119 but OSU at #155.
In short, I don’t see a major difference in rankings between OSU and Purdue.