Here are all of the Modern Warfare 2 PC specs: Minimum

Modern Warfare 2 PC MINIMUM & RECOMMENDED REQUIREMENTS

MW3 system requirements

Call of Duty Modern Warfare 3 System Requirements

Every Call of Duty Install Size Compared, From 2003 to Modern Warfare - IGN

Modern Warfare 2 has four whole sets of specs for the PC version

Call of Duty®: Modern Warfare® III - Multiplayer Free Access - Call of Duty

Call of Duty advanced Warfare: System requirements

Call of Duty®: Modern Warfare® 3 (2011) Collection 2 on Steam

Call of Duty®: Modern Warfare® II Launch — Everything You Need to Know Before the New Era Begins with Campaign Early Access*

Call of Duty®: Modern Warfare® 2 System Requirements — Can I Run Call of Duty®: Modern Warfare® 2 on My PC?