If Autoload Size shows SHOULD FIX warning it means it is bigger than ideal.

WordPress contains options in wp_options table in the database. Some options are autoload, which means WordPress will load them automatically for every pageload. The ideal size is less then 1Mb. If it is bigger it won’t be a show stopper, but your site will use more memory for every pageload, which can cause higher memory usage and slowdown.

How to Clean up Your wp_options Table and Autoloaded Data