Antimalware Service Executable is a Windows Security process that executes real-time protection against malware. It is also known as msmpeng.exe and is a component of Windows Defender. The program runs in the background and scans files and programs from time to time to detect viruses or other malicious attacks. When it detects any malicious activity, it deletes or quarantines them. The main reason that Antimalware Service Executable uses too much CPU is that it runs constantly in the background and actively scans programs and files. If you notice that Antimalware Service Executable is using too much CPU, there are several ways to fix it, including changing Windows Defenders schedule, adding Antimalware Service Executable to Windows Defenders exclusion list, and checking real-time protection settings. However, it is important to note that disabling Antimalware Service Executable puts your computer at risk of contracting digital viruses that would otherwise have been dealt with quietly in the background.