I'm on the other side of the fence, having had 8GB for a long time and upgraded last year to 16GB without ever having much troubles with Bugsplats. So there definitely has to be another factor involved than merely memory capacity.
Replays have been mentioned above, which doesn't seem unlikely, considering that locking the replay folder also notably increases performance on struggling systems (especially if the system is weak and doesn't have lots of RAM).
It doesn't add up. This is the only game that gives me problems. I can run Battlefield 1 on ultra, totally maxed out at 1080p at 90-120 fps lol. How come CoH2 just runs like a drugged up hog with only one leg?