What is the maximum refresh frequency of Xiaomi Gaming Monitor G27i?

The maximum refresh frequency is 165Hz (requires output device support such as PC graphics card). To change the refresh rate path in Win 10 environment, you need to right-click on the desktop--Display Settings--Display--Advanced Display Settings--Monitor--Screen Refresh Rate
If the Monitor is a Win11 system, right-click on the desktop--Display Settings--Display--Advanced Display Settings--Screen Refresh Rate.