How much RAM the game will use depends highly on how the OS decides to allocate it. If you have only 8GB of memory then the OS is not likely to gvie you mroe than 4GB just so the system doesn't die from swapping. If you have maybe 16GB you might see more. The game may also be capped internally to ensure the game doesn't eat up memory like a brownie convention beside a Weight Watchers meeting.
The reality is 'memory usage' is not like the days of XP where you had to manually kill stuff and move memory around. Modern OS are far far better and know better how to manage memory. Those silly 'GAME BOOSTER" tools are almost univerally useless given the way anything other than XP operates.
The biggest damn memory hog on my system is Firefox