This is an update to simmythesim’s Simulation Lag Fix for the latest version of the game.

It was also previously maintained by Xerox on Mod The Sims, but they no longer are keeping it updated.

I have been updating the mod for quite some time now via the comments on Xerox’s MTS page. But decided I should post it here so I do not forget to update it in the future.

I have not changed anything from the original mod, I simply just updated the python code and patched it for the most recent update for The Sims 4.

If you use MC Command Center to adjust the “Game Time Speed” in the game manually, DO NOT use this mod. 
By Manually I mean: “MCCC > MCCC Settings > Gameplay Settings > Game Time Speed” This should not be adjusted in MCCC if you use Sim Lag. Leave it alone at the defaulted to 25 in MCCC. 

If you use MCCC but do not adjust the “Game Time Speed”, you are fine. 

Compatible with TurboDrivers Simulation Unclogger. 
These mods do two completely different things, and I highly recommend grabbing TurboDrivers mod to use with Sim Lag Fix.

What does this mod do?

“This mod alters the game’s time speeds so that sim autonomy does not cause massive simulation lag in instances where there are many autonomy requests.”

This should eliminate, or at the very least, alleviate, the following problems:

  • Sims head bobbing
  • Sims doing nothing for a few hours
  • time slowing down on speed 3
  • time going back to the past


Mod Explanation

This seems rather basic, but there’s a video showing a scientist experimenting in GTW without the mod:

Here it is with the mod installed:

Everything runs much more frequently now, preventing the “bobbing head” effect. I haven’t experienced any time rolling-back since I made the mod!


This mod overrides the following python functions:

  • time_service.TimeService.start
  • time_service.TimeService.update

and overrides the following XML:

  • Clock – E81E51B398141F79
  • Time_Service – 2BE55516548A9522


Unzip the mod files into your mods folder.
Make sure script mods and custom content are enabled in your game!

If you have bugs after updating normally, follow these steps:

1. Remove the previous version of Sim Lag Fix and Clear Your Cache.
2. Start your game with Sim Lag Fix removed, progress in your save 1-2 sim days.
3. Save your game, then close it.
4. Install the new version of Sim Lag Fix, and enjoy!

Additional Credits:

simmythesim for the original mod & page description


NOTE: If you have any issues with this mod, or want to report any bugs please do so in Discord under the #bug_reports section. This is the best way to get quick and easy 1 on 1 help. 


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