I've installed Ubuntu 16.04 but my PC starts to run fan at maximum speed when I log in. Once installed I tried to find where the problem is, so I have installed lmsensors, fancontrol and psensor. All temps are o.k. (about 30 °C) but fan speed is -1 RPM (on Windows and on Ubuntu 15.10 fans work correctly). Changing video driver (from X.Org to nVidia driver) fans work correctly (and on Psensor fans are about at 2200 RPM) but my battery runs out quickly because of the nVidia Geforce GTX 960M. If I go back to X.Org video driver the problem returns. I have tried  to install laptop-mode-tools too, but the problem remains. How can I solve this problem and continue to use X.Org driver?
Thank you so much and sorry for my English.
P.S.: this is the result of sensor using nVidia driver
acpitz-virtual-0
Adapter: Virtual device
temp1:        +38.0°C  (crit = +103.0°C)
coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +39.0°C  (high = +100.0°C, crit = +100.0°C)
Core 0:         +36.0°C  (high = +100.0°C, crit = +100.0°C)
Core 1:         +36.0°C  (high = +100.0°C, crit = +100.0°C)
Core 2:         +34.0°C  (high = +100.0°C, crit = +100.0°C)
Core 3:         +34.0°C  (high = +100.0°C, crit = +100.0°C)
asus-isa-0000
Adapter: ISA adapter
cpu_fan:     2100 RPM
temp1:        +38.0°C
EDIT:
I have solved my problem installing Linux kernel 4.6.0 (Ubuntu 16.04 has Linux kernel 4.4.0). Here's a guide to install it and here another solution for my problem (tested) that use Linux kernel 4.3.5.
The second solution slow down system start, so I have used the first one
 
     
     
     
     
     
     
    