What would cause the difference in filter load speed between Chrome and Firefox?

What would cause the difference in filter load speed between Chrome and Firefox?

I have a  news aggregator page  built using jQuery that has multiple filters based on WordPress categories. The company filter has a large number of companies. When the + button is clicked in Chrome to expand the list and view the list of companies, it takes 6-8 seconds for the entire list to become visible. In Firefox, the list is visible almost instantaneously. Could someone help me investigate what might be causing the difference in load times across browsers?