Everything is so slow, and kinda make me wish that this was just a renpy or a twine game...
Ren'Py or Twine... Just save some money for a few upgrades.
There's been a fair number of minor lighting enhancements that have required a bit more "oomph" from hardware, particularly when it comes to the amount of RAM for extended periods (two hours or more).
It can be alleviated somewhat by running it from an SSD, but even that is a minor improvement in performance compared to better processor, graphics card and more RAM.
It can run on an old Intel i3 and 4GB DDR3 RAM, and from a HDD, as long as the graphics card is semi decent (anything from the last five years)... It's nowhere near as good as running on current low-mid range systems, but it's doable, and without sacrificing visual quality too. Only downside is loading times and scene/area transition (more loading) times.