Where to Find Site Speed Suggestions?
You can find the site speed suggestions under site speed section in behavior tab in Google Analytics.
The speed suggestions section displays 4 columns namely Page, Pageviews, Average Load Time, Page Speed Suggestions and Page Speed Score.
Page Speed Insights
The page speed suggestions column displays the page speed insights report and scope for improvement. It also displays a score in the range 1-100, the more the score the better the speed.
Why Optimizing Speed is Important?
Page speed is an important factor for search experience optimization. Users are more likely to spend time on the site which loads faster as opposed to sites which takes time to load. Hence, this extremely useful feature will help the webmasters to take actions on slow pages of the site in order to improve the search experience of the user.
Also See:-
Page Speed Important for Ranking
Google Search Quality Updates
mod Page Speed for Apache
Search Experience Optimization
Google Shares Views on Guest Blogging and Links
EMD Update
Page Layout Algorithm
Google Plus and Seo