I'm using Ubuntu 18.10 with Linux 4.18.0 Kernel on Ryzen 1700 with NVidia GTX 1050 graphics card. The graphics driver is Nouveau.
I recently used UKUU to update the kernel to 4.19.2.
However, after the update, I faced random slow downs within 5 minutes to an hour after boot. It all goes well when suddenly the system just comes to almost a halt. The mouse pointer moves at a glacial speed and the caps lock light usually responds 30 seconds after being pressed.
I have reverted back to Kernel 4.18 and the problems have gone away.
I have checked the syslog but there is nothing out of the ordinary. The behaviour of kernel 4.19.2 is quite similar to memory leaks. But I have Conky installed, and I monitored memory and CPU quite keenly and there is nothing hogging resources.
How should I diagnose the problem?
As an aside, is it safe to clear existing logs in /var/log? Fresh logs might help me to zero in on the problem.