Cache the output of your blog widgets. Usually it will significantly reduce the SQL queries to your database and speed up your site.
Yep, WP Widget Cache is a plus for them, as it reducing the cost for caching a new page
View the source of your site page, there maybe some code like this at the foot:
<!-- ** queries. ** seconds. -->
If not, please put these codes in your footer template:
<!-- <?php echo get_num_queries(); ?> queries. <?php timer_stop(1); ?> seconds. -->
After using the WP Widget Cache, I think you'll find the number of 'queries' reducing a lot. Of course, that will depend on how many and what widgets you use, some sites can gain more than 70% improvement.
You can have a look at the source of the web page, and search
<!--WP Widget Cache End -->