Head to Nox Player official website and see if they have released a new version. If you think your PC has no problem and is not causing any lags, perhaps it’s the emulator itself. Usually, upgrading can also improve speed. If you haven’t updated Nox Player in a while, it’s time to upgrade it. Some background programs may be unnecessary too, so look for those that are consuming a lot of memory.
These usually appear on the top of the list.
Simply head to the Task Manager and end all non-essential programs. The more apps that you have running, the more memory they eat up and leave less for the emulator. It could be that other third-party programs are causing the lag in Nox Player despite having enough RAM and CPU power in the system.