I am running Ubuntu 16.04 on my laptop HP Pavilion G6 2320tx. The specs are:
After using it for 10-15 minutes, everything starts lagging. Clicking anything takes time to open up and everything becomes super slow.
I have done top but none of the processes is taking RAM or CPU.
Everything looks normal.
If your cpu gets hot because the heat sink of your cpu ist covered by dust or the cpu fan not working the cpu might be throttled to prevent overheating. See here
My fresh Ubuntu 16.04 was also lagging, window, mouse etc. Found out that Nvidia drivers were missing, so it could not handle my two FHD and my 4K monitor at the same time. Worth upgrading the CPU and GPU drivers if you also experiencing lags.
Pop into terminal and type:
sudo gedit /etc/sysctl.conf
... and add this line to the end:
vm.swappiness = 15
... which will tell your system to use physical memory instead of virtual and speed up your desktop. The default is 60 which is too high and relies on virtual memory more which can cause slowdown after a time. Reboot after change.
