Instructions
Launch "Assassin's Creed II" by clicking on its desktop or "Start" menu shortcut. Access the game's settings by clicking on "Options," then click on "Graphics." Lower all graphics settings to "Medium" or "Low." You can also reduce the game's resolution to lower the processing load on your graphics card.
Close all programs that use your Internet connection every time you want to play "Assassin's Creed II." Since the game regularly connects to Ubisoft's servers to ensure you hold a legitimate copy, you need to maintain an acceptable connection speed while playing. This will allow you to avoid any lag when reaching a save point.
Upgrade your graphics card or add some RAM to your computer. "Assassin's Creed II" requires a powerful computer to run properly. Ubisoft recommends you run "Assassin's Creed II" on a computer with a dual-core processor with two gigabytes of RAM, and a graphics card with at least 256 megabytes of RAM. However, those are minimum requirements, and you may still experience some lag with such a configuration.