The new Nitro Javascript engine supposedly allows Safari to render webpages in blazing speeds, making it over a 30 times more efficient than IE 7 and almost 3 times faster than Firefox 3.
It also carries support for HTML 5 and CSS3 which makes it perfect for developers and future web technologies.
Some of the key new features in Safari 4:
- Top Sites, Safari 4 Beta tracks the sites you browse and presents them as thumbnails on a single page.
- Cover Flow, It provides a highly visual way to sweep through your sites and bookmarks (just like in iTunes).
- Tabs on Top, Tabs now appear on the top of the window like in Google Chrome.
- Windows Native Look, Safari now has a native theme for when run on Windows XP or Vista.

