After seeing that TSW5 supports 8gb ram devices I decided to get it, but as soon as i spawned a train the game just froze, even with it on the lowest settings. I feel like this is a scam since 8GB devices clearly dont work for the game. even if you get into the game, your stuck with a no texture laggy game. My device could handle tsw4 fine but now tsw5? not the same. Some sort of potato mode would be cool, but even after uninstalling everything, and doing EVERYTHING << possible, it wont work. So i suggest not supporting 8GB devices as it clearly doesn't work.
The initial runs will have lower performance due to shaders being built. Also what's your other systems? What's your gpu. What's your storage? What's your cpu? Resolution?
Just like rennekton says, the first runs are always not good as the shaders are compiling, and performance does improve after a run or two on the same route. This effects all systems to some extent. You could upgrade your ram to 16GB which is a fairly cheap and simple DIY upgrade even on a laptop. Posting your spec here will help.
8GB of RAM is not enough for most games these days. 16GB is a minimum along with a solid GPU/CPU combo with 6 - 8 GB of video ram..