You may not be much satisfied with the new look of IE9 if speed matters to you. Previous versions of IE have proven to put a lot of pressure on your computer resources - taking much time to load all the add-ons, etc., before presenting you with the home page.
The best answer to the question - what is new in IE9 - would probably be that it employs 100 percent hardware acceleration. No other browsers use this method except Google Chrome, which employs partial hardware acceleration.
NOTE: For a side-by-side comparison of IE9 and Chrome, please read my article IE9 vs Chrome.
Speaking honestly, the IE team has set a trend that other browsers now need to follow if they are to remain in the market. If you experience slowness in speed, check out the very first option in the Internet Options. If the option saying Use Software Rendering… is grayed out, either your graphics device is not compatible or you need to upgrade the graphic drivers.
Reduced Add-ons
For maintaining the speed, IE9 does not contain many add-ons as in the previous versions.
If you install add-ons and components to the browser, a notification bar pops up at the bottom of the window asking you if you wish to manage your add-ons. It allows you to open the Manage Add-ons dialog that shows the load time of each IE Helper (add-ons and other components).
You can check the time and disable certain add-ons that you may not want to use all the time. Thus, the IE9 allows a faster startup and speedy browsing when compared to the previous versions of Internet Explorer.
The Notification Bar May Be Annoying: The Notification bar also appears when you are downloading something or when IE9 blocks a popup. It also helps you store passwords for each site you visit. However, there is something negative that I noticed about the notification bar. The placement and color of the notification bar is such that it almost dissolves into the background and many a times, I miss it. Obviously, other users too might miss it, thereby ignoring the prompt to save password or missing out when it asks about a new add-on. To close the notification bar, you will have to use the mouse and click on the X button. I am still looking for a keyboard shortcut that closes the notification bar.