Thank you for posting your inquiry here in Microsoft Community, MauroCutrona.
This is normal, the fan of your Surface Laptop 4 is equipped to adjust it's fan speed (which most of the times will produce noises) to stabilize the temperature of the CPU to perform as expected while there are several things running in the background process, specially for new devices, there are lot of tasks to complete (includes synchronization and updates on the background).
We also would need to check environmental conditions which can cause fast fan speed. Here are the methods that we suggest to reduce potential heat-related issues, follow these guidelines:
- Keep your device and its power adapter in a well-ventilated area when in use or charging. Allow for adequate air circulation under and around the device. Use caution when operating your device on a pillow, blanket, or other soft material, because the material can block the airflow, and this may cause device overheating.
- If device is being used in warm environment or in the Sun move device to cooler environment.
You can also adjust on how you want your CPU to perform, by selecting the battery icon on the task bar and adjusting the power mode. Setting the power mode to Recommended throttles the CPU and helps keep it running cooler with less need of assisted cooling. While a setting of Better performance or Best performance will allow the device to run more quickly, it will also allow the fan to come on more often to keep the CPU cool and performing it's best.