Performance issue with my system
Solution 1:
If your high CPU usage is not being caused by malware, as you already mentioned in your question, then your laptop may have an overheating issue. You can check this by installing a CPU temperature monitoring application like SpeedFan.
If your CPU temperature is too high that might mean that it is time to bring your laptop to a computer repair technician for routine maintenance to clean out the dustballs from the aluminum cooling block under the CPU fan. Or else as a temporary fix you can put an external laptop cooling pad underneath your laptop.