When you start typing something in Safari's address field at the top of the window, you'll be shown all sorts of suggestions from your search engine and Siri. These can be useful. But if you want to streamline and speed up things, then go to Safari, Preferences, Search and uncheck everything except Show Favorites. Then you'll get a cleaner list of suggestions from just your bookmarks and history. In fact, it makes it a handy way to search your browser bookmarks.