A typical game will simulate tens of thousands of entities at once, and it all needs to be updated. You can't cull by LOS because the simulation is running everywhere. There's a lot of what amounts to collision checking, where robot arms are looking for items to pick up or space to drop them off.

It's still quite performant. Some of the larger factories people have built are truly stunning in scale, yet can run at 30+ updates a second. People can host games with hundreds of players with relative ease.

At the beginning of the game, even quite modest computers will have no trouble with it, but that's not a reflection of what the game is about. Big factories are much of the point.

The facilities that you create in the game can be quite large and complex. These facilities can be processing and tracking maybe tens of thousands of different individual items. There’s a lot of stimulation workload when you reach large scale.

Unlike in a lot of games where the computational complexity is all graphics-oriented and done in the GPU, these computations are largely all CPU.

Modern laptops should generally be fine though.

I haven't looked at them, but anything slightly modern should do. My laptop (5 years old), the desktops in school (2-3 years old), my girlfriend's laptop (3-4 years old), my cousin's laptop (another girl with a not-so-beefy laptop), and my brother's laptop all run it fine... Most of those don't even have dedicated GPU.

Sure, once you go megabase scale, after a few hundred hours of playing, most hardware will lag a little. But at that point there are millions of objects the game has to track every loop, there isn't terribly much that can be done about it. The game doesn't aggregate like OpenTTD, where the number of passengers at a train stop is just a number. Because of the way it works, every piece of iron ore in a train station in Factorio is a separate object existing somewhere. (Though they do some tricks to abstract that a bit as well, see their belt compression blog posts.)

I play it on a Thinkpad T410 with an i5-M520 and it runs fairly decently. If an old laptop with a first generation i5 can run it, anything can lol