Want to give AE more power to devote solely to your render? Try these tips to dedicate your computer's power.
Choose Edit > Purge > All to release any RAM being held by previews or cache files
Close the Comp Window (unless you like watching paint dry). This will free up more memory and computer resources for the render. The more layers you have, the bigger benefit in closing this window.
Quit any other applications running.
Leave After Effects as the foreground application (in other words if you need to check email or play solitaire, use another machine).