OpenCart Aggregate Rating-Reviews plugin helps to display the aggregate rating of the particular category of your store. It displays top rated reviews, comments given by users. It will not affect the speed of your category page because plugin cache the aggregate rating and top reviews for next time. Please find below the list of features -

Features

Calculate the aggregate rating of a category by reviews on products

Aggregate Rating Rich Snippet

Autocaching of rating and reviews

Remove caching option from admin

Display slider of customer reviews

Tested with Default Theme only. If it is not working in custom them then ask for support.

For installation guide please click here.