IE9 exhibits slow performance while 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 However, some outdated video cards and video drivers do not support GPU hardware acceleration.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:

1. Start Internet Explorer 9.
2. Click Internet Options on the Tools menu.
3. On the Advanced tab, locate the Accelerated graphics section.
4. 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.

<

p>Reference: You experience slow performance in Internet Explorer 9