Whereas antivirus software provides a basic level of protection for your system, full internet security expands on capabilities such as scanning files and software, activity monitoring and vulnerability search with features tailored for Internet use.
Indeed, many internet security products are marketed as ‘suites’ because they contain several different programs that can be accessed by a single interface.
These might include a firewall, anti-spam controls, ad blockers, webcam protection, keylogger protection, parental controls and credit card safeguards. There might also be additional protection against web-specific types of malware such as spyware and adware.
However running so many different types of program might mean that internet security suites use more of your system resources than conventional AV.