I installed ubuntu 18.04 after that my laptop getting hot near touchpad.I installed tlp but it didn't help.
Getting hot near touchpad might mean your Hard Disk is overheating. It is more common in machines having 2GB or less RAM.
Step 1 (Decrease Swap Usage):
Open the Terminal and run:
sudo -i gedit /etc/sysctl.conf
Scroll to the bottom of the texts, create a newline and paste the following two lines:
# Decrease swap usage to a more reasonable level vm.swappiness=10
Save the file and reboot the machine.
Step 2 (Enable HDD Spindown):
Download and open Disks (gnome-disk-utility) app. Click the cogwheel icon on the top right and select "Drive Settings".
Active Standby. Grab the slider of the “Standby Timeout Setting” and increase it to 20 minutes. Click OK button and give password to authorize the operation.
Go to the next (APM) tab. Active “Apply Advanced Power Management Settings”. Make sure APM level is not more than 127. Select OK and authorize the action using administrator password.
On my laptop, when booted 18.04, average CPU frequency is much higher in comparison to installed 14.04.
Current install is 14.04, fully updated, fan-less Acer laptop, 4GB ram, CPU Intel N2840 (up to 2.16GHz) based on cat /proc/cpuinfo. Avg CPU frequency around 600MHz based on cat /proc/cpuinfo most of the time when laptop is doing nothing.
Booted on this laptop 18.04 from USB, not installed. Laptop is doing nothing. CPU is running above 1GHz all the time, most of the time closer to 2GHz. Kept an eye on it for an hour, just looking at new interface, etc. CPU hovering between 1.2 and 2GHz.
Rebooted back to 14.04, CPU frequency is back to 500-700Mhz range.
I had a similar problem. turns out it was actual high load that forced the cpu clock speed to always be more than 3GHz on all (!) cores. namely the xorg (>100%), systemd-journald (>50%) and rsyslogd(>30%) were consuming a lot cpu power. in the journal i could see the following line over and over again:
SynPS/2 Synaptics TouchPad: Read error 9
After a bit of digging I found that the synaptics driver should be replaced with the xserver-xorg-input-libinput. (which I had already installed, maybe that was the problem)
So after removing the package xserver-xorg-input-synaptics the cpu load went down significantly and so did the cpu-clock and heat.