Improve Safari Performance:
Safari does all sorts of things automatically to enhance your browsing experience. Of course anything automatic consumes system resources. One option would be installing software, such as ClicktoPlugin, that prevents Safari from automatically loading plugs-ins.
Software like ClicktoPlugin not only speeds up browsing, it reduces fan speed and extends battery life. It also improves performance of audio and video streaming.
The way it works is that It replaces any plug-in object with an unobtrusive placeholder that can be clicked on to load the embedded content of the plug-in. Now plug-ins only activate manually.
Another option you can do instead of or in addition to using a plug-in management Application would be to uninstall Adobe Flash.
Without Flash and plug-ins Safari performs better.