In my case (and in most cases, i think) it’s not a RAM problem, but CPU. If you see from my test, 30 CPU-hungry VSTi instances (like Kontakt or Battery) are having a serious impact on CPU even when nothing is playing and no samples loaded in them.
Latest song arrangements i’ve made with using Instrument tracks instead of VST Rack and it is significantly more intuitive to tweak, route, automate, mix etc. (for me, at least…)
These were no so big arrangements - 15-25 instruments, multi-out drum VSTi and 15-20 group and FX channels, about 5GB RAM used and my CPU reaching limits with 128 samples buffer size. Which means when i face a 100+ tracks project, i will be forced to 256 samples and even 512. And 512 is will make all guitars and drums recording pretty hard… I actually expected a bit more from a new computer which cost me 2k dollars 