Site speed is considered as one of the ranking factors considered by Google for websites in their search results, the faster your site loads in less time the better its for you Google thinks this in users point of view, Google made available site speed report for Google Analytics users few months back which they need to add tracking code, today Google Analytics team announced in their blog post that Google Analytics Site Speed report available to all users on new version of course, without the need to modify/add any code on your end.
Accessing Site Speed report in Google Analytics
Sign into Google Analytics (new version), expand Content section on left and select Site Speed which shows three tabs on right-pane with Explorer, performance and Map Overlay.
Explorer gives overview of site load time, performance tab buckets your site speed performance by page load time. Map overlay shows how users in different geographic regions experienced your site speed.