You experience slow performance in Internet Explorer 9

SYMPTOMS
When you browse a webpage by using Windows Internet Explorer 9, you may experience slow performance. However, this issue does not occur if you view the webpage by using an earlier version of Internet Explorer.
Note This issue may be more noticeable when you browse webpages that have more complex graphics.
CAUSE
This issue can occur if Internet Explorer 9is running in Software Rendering mode.
By default, Internet Explorer 9 uses GPU Rendering mode. However, some outdated video cards and video drivers do not support GPU hardware acceleration. If Internet Explorer 9 determines that your current video card or video driver does not support GPU hardware acceleration, Internet Explorer 9 uses Software Rendering mode.
To determine whether Internet Explorer 9 is using Software Rendering mode, follow these steps:
Start Internet Explorer 9.
Click Internet Options on the Tools menu.
On the Advanced tab, locate the Accelerated graphics section.
Verify that the Use software rendering instead of GPU rendering check box is selected.
If this option is selected, Internet Explorer 9 is running in Software Rendering mode. If the option is greyed out, your current video card or video driver does not support GPU hardware acceleration.