If it helps, I recently did a whole bunch of testing to see what RAM and VRAM usage looked like across the range of settings, and 1 vs 3 screens, on my PC…
Keep in mind, my PC is very different and built last year, and so these results will not reflect how any other PC uses resources or performs, but it might be useful in a general sense to see what MSFS uses when it has room to do so…
Look at what the PhysicalMem and GPUMem values are - but keep in mind Windows itself has overhead too:
