This truly depends on the kind of lag you have; In general taking these steps will greatly reduce lag; 1. Cleaning your computer with a program such as CCleaner; CCleaner - Optimization and Cleaning - Free Downloadⓘ 2. Optimizing your system with a program such as Tune up Utilities {Remember to defrag as well} ; TuneUp Utilities? 2011ⓘ 3. Closing all unnecessary programs while in game. 4. Running a virus scan prior to playing {Viruses slow down your computer entirely.} 5. Setting your graphics to low in the Crossfire game { Via Options } 6. Updating your drivers; Driver Update - How Do I Update Drivers in Windows? - Update Windows Driversⓘ 7. Buying a new Graphics card. 8. Switching to a wireless internet {Or Internet service provider.} Good luck!