WordPress is a pretty awesome content management system. Many folks rely on it to power their websites. The plugins that you install do affect how your site performs though. Debug Bar for WordPress is a handy plugin that lets you figure out how fast your site is and the queries that are being run.
Debug Bar is pretty elegant. It shows you PHP and MySQL information. The script shows total queries, query time, and memory usage. The script also tracks PHP warnings and notices, so you can find and fix the issues with your site easier.
Debug Bar does not necessarily tell you what’s wrong with your site. But it puts the relevant data where you can’t miss it easily. This is a free plugin.