And because of this reason, the computer starts working slowly and shows various problems or errors. It can be seen taking up more than 50% usage of CPU when you open the task manager. Operations like background scanning process, cleanup of computer, removal of viruses, and full scan of new websites or files accessed by the computer are performed by it.ĭue to these operations, the problem of Avast service high disk taking up CPU arrives. Avast Antivirus performs various operations to prevent viruses and to perform these, it requires resources.