Modern Warfare is typically the free version which has a huge map. I wouldn't worry about it personally. That game is a resource hog and RAM usage probably goes up and down quite often. I still use 16g and have no problems running it.
Call of Duty: Warzone System Requirements | ||
Minimum | Recommended | |
CPU | Intel Core i3-4340 or AMD FX-6300 | Intel Core i5-2500K or AMD Ryzen R5 1600X |
RAM | 8GB | 12GB |
HDD | 175GB HD space | 175GB HD space |