32GB still makes sense since Windows 10 will refrain from using the pagefile as long as you stay under 50% physical ram in use (under 16GB total). And Windows will use the rest to cache files to speed everything else up.
Before the XBox release 32Gb wasn’t enough, I’ve seen the sim go up to 41GB on my system, others reported over 50GB in use. However those extreme cases were bugs.
I did my test flights again to measure data use and ram use for different terrain settings. My test flight is from London City to Heathrow in the Bonanza, clear skies, noon, 500ft cruise altitude. Flying slow enough to make sure all data can be read.
Object detail stays on 200, buildings etc on Ultra, putting my weak GTX 1060 6GB to the test
(testing on a laptop, 2.2 ghz i7-8750H, boost disabled, 1080p)
First number is data downloaded during the flight, then
Max committed ram during the flight / peak CPU ram / peak GPU ram
SU6 London City to Heathrow, 500ft, Bonanza, noon, clear skies
No PG Data
Terrain 800 0.87 GiB 20.5 / 15.6 / 5.2 8-15 fps
Terrain 400 0.60 GiB 16.4 / 11.4 / 4.4 15-22 fps
Terrain 200 0.38 GiB 12.1 / 7.7 / 4.1 21-22 fps
Terrain 100 0.23 GiB 11.6 / 6.8 / 3.7 22-25 fps
Terrain 50 0.17 GiB 11.1 / 6.4 / 3.6 22-24 fps
PG Data
Terrain 800 5.45 GiB 20.8 / 15.5 / 5.5 7-14 fps
Terrain 400 3.76 GiB 15.5 / 10.4 / 4.4 14-22 fps
Terrain 200 1.95 GiB 12.5 / 8.0 / 3.9 21-27 fps
Terrain 100 1.26 GiB 11.1 / 6.9 / 3.7 27-30 fps (22 on autogen)
Terrain 50 0.65 GiB 10.5 / 6.8 / 3.5 31-32 fps (22 on autogen)
Newark KEWR to Laguardia KLGA, Bonanza, 800ft, noon, clear skies
PG Data
Terrain 400 2.77 GiB 19.0 / 12.4 / 4.5 13-19 fps
Terrain 200 1.77 GiB 12.3 / 7.1 / 3.9 18-29 fps
Terrain 100 1.02 GiB 10.8 / 6.5 / 3.0 25-36 fps
For Terrain 400, which is the new UI maximum since SU6, 32GB is definitely recommended.
My GPU ram usage measurements don’t mean more VRAM doesn’t help, the game will use the extra VRAM and keep more data on the GPU for when you turn the camera around. My GPU ram usage jumps up when I turn the camera and then I get stutters when it’s hitting the 6GB physical limit.
Now add mods, 4K rendering or higher, clouds, live traffic, multiplayer and 32GB ram will start to feel cramped. Yet as I’m currently flying at FL380 over open ocean (or rather over an ocean of clouds) at terrain detail 200, it’s only using 9.4 GB of ram.