Factorio Forums

I've had this issue for months now, going back several versions. I don't know what causes it and it happens with VSYNC on and off. The save I attached in my previous bug report exhibits this behaviour (just disable the scrap handling setup as it was causing unrelated issues with my UPS.)

My specs are as follows:

CPU: Intel i5 10400
GPU: RTX 2060
Motherboard: B560M-A
RAM: 16GB
Storage: 2TB SSD

I genuinely do not know what would cause it. It first started shortly after I first installed mods and has persisted through every iteration of my mod folder and through every save I've started since then.

After some testing in my current save, I can somewhat consistently reproduce the Flip lag by zooming in and out of areas with coverage that haven't been loaded in a while.

Check your RAM and swap usage.

Usage is stable while Flip lag persists.

You mean zero swap use? RAM usage is sitting at what value while playing?
Next, I assume you are playing on Microsoft Windows operating system:
1.Please check Windows Event Viewer, System tab, for any errors.
2. Reinstall GPU drivers, make sure to use most up to date version.

Nothing else comes to my mind which could slow down your game, sorry. Maybe your base is so big CPU isn't handling it, haven't checked your save. Please pin URL with your save in the first post, to make work easier for Factorio developer looking at this report.

This is a snapshot of memory and the Event Viewer. Flip lag occurred several times during this.

I've attached my up to date save.

I highly doubt my base is the issue since Flip lag was occurring before I even left Nauvis. Even now update only takes ~2.5ms.

My GPU driver is up to date.

I think it's the RAM. You have too many programs open. Your RAM use it at 88%, it probably means, swap is being used too. Open Task Manager (not Resource Monitor), I think there you can see swap use. Swap is an "additional RAM" on the hard drive, much slower by definition, OS is using it when RAM is full (like yours is).
It is possible that, with your RAM being fully utilized, Factorio have to wait for certain assets to load back to RAM, and you are experiencing UPS/FPS drop while it happens.

To test it out, you should close everything and unload all icons from system tray, then try to play Factorio, while monitoring RAM.

This is only with Factorio, Steam, and Lightshot (what i use to take the screenshot) active. Everything else in the system tray is disabled. I am still getting Flip lag.

My guess was right, it's the RAM.
Your RAM is completely exhausted (100% allocation), hence you experience problems. This is not Factorio's fault.
Still no Task Manager screenshot from you, so can't tell how far you go above physical RAM allocation.

What do you want to see from task manager and resource monitor? Going to do another snapshot once I know what to show.

somepersondontask wrote: Tue Jul 22, 2025 1:59 am What do you want to see from task manager and resource monitor? Going to do another snapshot once I know what to show.

Screen like this (pulled it out of search results) will show your physical RAM and allocated memory. I don't use Windows, so there may be a better tool.