Many reasons can lead to your ASUS laptop lagging. You can find solutions from these aspects:
1. Try updating the Graphics card if it is outdated since it matters much when you play games.
2. Of course, you can upgrade RAM if it is insufficient.
3. Faulty hard drive also may cause computer lagging. Run Command Propmt and use '''chkdsk x: /f''' to check and fix some logical errors.
4. You can also choose to upgrade OS.
Find more information here: https://www.minitool.com/partition-disk/my-computer-lags.html