I am just dropping this as maybe useful info.

I am running seablock 2.0 with pretty large base. The sleep timer for some reason was above where it should have been, which led to a UPS loss.

When I increased the game speed my PC could handle up to 5 times the speed of the game so hardware wasn't the issue. I also checked a lot of things like G-sync and the regular offenders.

After removing this mod the sleep timer went down to what it should be and the game was again at 60 UPS. However this did happen after my base got larger. I can share a save if the creator of this mod wants to look into it. It's pretty specific.

What do you mean by "sleep timer"?

After removing the mod, can you try adding the mod again? Does the issue reappear directly or does it work fine for a while?

I meant the sleep time in the UPS metrics. The time the game sleeps before the next frame is processedWith the mod all of the UPS metrics are fine, but the game seems to sleep longer than it should causing a drop in UPS and FPS to around 57.

My sleep time is at 8 instead of what it should be for the UPS to add up to 60 which would be 5. My guess is there is some calculation happening in the background that is slowing down the game. And since the sleep time is above 0 the game should be at 60 UPS.

I have around 550 trains in the network.

The issue appears only on this save and after around 400+ trains and it reappears with the mod on.

This mod is very train-related so it's just natural that 550 trains will have an effect on UPS. And a drop to 57 doesn't seem that big IMO.

Mods cannot do anything "in the background" like other software does. There's not the concept of threads in Factorio mods.

I have no idea of how Factorio's loop works and how the mods work. However I can tell you that my PC can handle the base with the 550 trains at 60 UPS WITH the mod as well as without the mod.

With the mod I can set the game speed at 1.2 and i get 60 and something UPS. So it's not a hardware limitation but some sort of miscalculation of the sleep time. I just want this to be clear. There is some bug somewhere but yeah, I'm not a mod dev.

I think any question you have about the sleep time is better asked to the Factorio devs than me. I can't answer why your UPS isn't what you expect it to be and how the sleep time works.