2.8 seconds for superfish menu – why?
For each anchor tag – superfish performs some actions. As you can see from the code-snippet of the for-each function – the $a.eq(i) could be replaced with a $(this). This alone would save about 20% of performance.
Performance Analysis of different Menu Sizes
Based on this superfish example I created a sample page with 3 different sized menus: 50 elements, 100 elements and 500 elements. The page has 3 buttons – each triggers the menu creation and makes the correct menu visible. Here is an example for the small menu: