Hi,
Unfortunately, it's important to note that directly limiting the CPU usage of System Center Endpoint Protection or Windows Defender to a specific percentage, such as 10-15%, is not a standard configuration option. Antivirus software like System Center Endpoint Protection and Windows Defender is designed to use system resources, including CPU, to provide real-time protection and scanning capabilities.
While you can adjust some settings to optimize resource usage, it's not advisable to forcibly limit the CPU usage of these security solutions. Doing so could compromise the effectiveness of the antivirus protection and leave your systems vulnerable to malware and other threats.