As I have understeanded, you are trying to find the lowest CPU temperature, which results in a quieter cooling fan. In my opinion, I don't think that it's possible to make the fan quieter (to lower the temperature) without having both lower CPU frequency and lower CPU usage.
But you can make the fan quieter if you have a power saving/silent mode option embedded in your BIOS (which may reduce the CPU fan rpm).
To keep it cool, try not to run intensive apps in the background.
Check to see if you have such an option or something similar in your BIOS settings.