I have a Dell XPS 15 9570 with an Intel Core i7-8750H and an NVIDIA GeForce GTX 1050 Ti. I have BIOS 1.10.1 and all drivers up to date. Moreover I have a dual boot between Windows 10 and Ubuntu 19.04. In Ubuntu I have the fans always on at 2500 RPM with a strange behavior. Meanwhile the system is idle the temperature on GPU increases from 40°C to 45°C in a few seconds. Then the system increases the fans speed to 3200/3800 RPM and the GPU temperature decrease to 40°C like before and the fans come back to 2500 RPM. But again, the temperature raise again and again the fans speed fast. If I want peace for my ears I have to switch the PRIME profiles onto NVIDIA X server settings to Intel (Power Saving Mode), but I have to give up the use of nvidia graphics cards. I attach the charts that shows this strange behaviour. On Windows 10 if the GPU workload is around 30%/50% and th temperature is around 50°C the fans runs fast and loud. I wonder why I have this strange behaviour. This has happened since my motherboard, my heat sink and my fans was changed. Thank you
In blue the GPU temperature and in red the fans speed.