I noticed a massive difference when I upgraded tbh, especially since I like to keep a load of stuff open.
I went from 8gb ddr3 to 16gb ddr4 @ 3200mhz, I've noticed my page file usage has gone down also. Arma tends to use ~10GB, then I easily have room to keep TS, discord, msi afterburner, Spotify, sometimes OBS, and a few chrome tabs open and I can switch between all of them seamlessly, if I tried that with 8gb it would stutter and take a few seconds to load each one from virtual memory.
RAM is expensive but if you like to use more than a few things at once and you have a CPU to handle the multitasking, it's definitely worth it.