Hello,

Your slowing is maybe due to the PNG opacity and the IE filter to make this effect. I replace the shadow of each box by a single color and  apparently the scrolling is better.

Try to redownload the template and replace the index.php and template_css.css file to take modifications.

Sorry for this inconvenience. 

Hi,

It's maybe due to the style of menu. On your first screen you use a "horizontal" style and on our template demonstration, style of menu is define like "list".
In horizontal, joomla use a table with spacing, but not for a list.

Else you can add a css declaration to #mainmenu :