Performance overhead is the extra computing cost that security tools add to a running system. It can show up as higher CPU use, more memory consumption, additional disk activity, network latency, or slower application response. In cyber security, overhead matters because defenses run on the same servers, endpoints, and cloud workloads they are meant to protect.
If overhead is too high, administrators may reduce logging, disable scanning, or delay updates, which creates blind spots attackers can exploit. Ransomware operators and hands-on intruders often target busy production systems where even small slowdowns are visible, so defenders must choose controls that stay effective without disrupting business services. Good security design balances detection, response, and containment against the cost of running those protections in real time.