CPU consumption of belts and other things

[Hannu]

I have read that belts consume high amount of CPU cycles. But what things (load, speed, splitters etc.) affect to it? I have couple of thousands empty belts in my area from depleted mines. Would it be better to clean them up or is it practically insignificant compared to base able to produce 700 k irons per hour? I have occasional lag, especially with wide angle view.

How about idle inserters, assembling machines, electric poles, logistic robots, train stations etc.? I have for example old base as some kind of museum. Maybe some hundreds of idle assemblers, mining drills and furnaces.

I try to get practical functionality, not the mathematical perfection. If I save 20 % CPU load and couple of FPS I am too lazy to clean up anything but if it causes significant lag, I have to do it.

[Frightning]

I believe empty belts have essentially 0 CPU impact, it's modelling the items moving on belts that can be CPU intensive if you have lots of belts with stuff on them.

[orzelek]

From what I understand it's the actually working belts mainly that cause CPU usage. Empty ones are inactive until something "wakes" them up - you can look at this in game with debug tools.
There was a trick to use underground belts to decrease CPU usage from belts that was very helpful in earlier versions before belt optimization (0.11). I'm not sure if it's still as effective - might be useful if you have a mod with longer underground belts.

Tried it in my base but it's hard to tell if it helped.
It seems for me that moving items from warehouses to compression chests is more helpful.

[Hannu]

OK. Thanks for the information. I will not care about old belts.

[Loewchen]

Underground belts are still very effective, at least when belts are close to maximum throughput. We managed to more than double the ups on our 1.2 Rockets/min Hardcrafting map upon replacement.