big map = long catching up

[Nexarius]

Why does it take so long to catch up on the map when you are trying to join a server?
It would make sense if my computer isn't fast enough but on a big map it takes me 5min to join while the CPU is only at 20%, RAM is 10GB used from 24GB, GPU at 5% and GPU RAM at 2,2GB of 4GB.
It doesn't make sense. Why is factorio not using all of my resources when it is clearly needing them?

[Neemys]

The bigger is the map, the longer you need to download it and there is also more entity, since you have more time to catch up and during this increased time there is more entity from when the map was smaller, it take more time to catch up.

Edit : factorio use only one core for the main loop

[Nexarius]

I don't mean that you have to wait longer to donwload the map.

I mean that catching up once the map is downloaded takes way too long probably because the CPU is NOT even used completly. (look at the screenshot even the cores that do stuff are still below 50%)

[DaveMcW]

Factorio is load balancing among your 8 cores, but it can only use 1 at any moment. That gives an average of 12.5% CPU use.

[Loewchen]

I don't mean that you have to wait longer to donwload the map. I mean that catching up once the map is downloaded takes way too long [...]

The longer the download took the more updates you missed and therefore the more catching up you need to do. Additional bigger save-files usually means bigger bases which means higher performance demand, so the catch up speed is not as high.