Lowest/Best Memory Allocation Possible For Stable FPS?

I have often asked myself the question "Why is it that adding more RAM doesn't add more game quality?" This, combined with the large amount of arguing about having a large allocation is better than small allocation and visa versa, lead me to do an experiment testing allocations between 128 Megabytes-1 Gigabyte (1024 Megabytes)

Here's a video of the result of my experimenting! The lowest allocation is 256 MB which leaves you at a normal FPS and a LOT of space to run extra programs such as screen recorders! ... https://www.youtube.com/watch?v=yYEgncEkIt4