Windows 7 ships with the full Aero experience, including animated menus, windows, tool tips, etc.
If you want (or need) to get maximum performance from your PC, you can turn off these visual effects and save RAM and CPU cycles. Your system will be faster, more responsive, and more stable.
Here is the path to the fully optimized best performance settings (see video for greater detail):
Start, Control Panel, System and Security, System, Advanced System Settings, Performance, Visual Effects, Adjust for Best Perfomance
See my other videos for more help and tutorials.