I have a really buff PC IMO:

  • 16GB 2800Mhz RAM
  • 12 Thread i7-3930K
  • SSD
  • gtx 780ti

And I've settled with only playing medium-size systems.

Yet the end-game events will inevitably lag my PC (especially a galactic war with two sides started by dormant empires waking up and fighting each other).

(I will recognize the lag I'm talking about with a medium-size galaxy is in no way comparable to the lag you get late-game with the biggest galaxies where there is an active /5 and up to /15 slowdown, here my end-game event is the prethoryn scourge and I'm on a medium-size, I'm just having a /3 slowdown and some stutter, but I just really don't like lag. Also, the whole app freezes for 3 to 30 seconds which can be a major hassle)

I'm willing to sacrifice a whole lot (I play almost only using the galaxy map and with a real macro approach to Stellaris in general. I'd be willing to let go of a lot of the less primordial simulations happening for every game tick, and even of battle visualizations):

What are your best suggestions to fix Stellaris' godawful optimization?

  • I can't answer as to Stellaris' technical specs, but do note that not all software can utilize all hardware to its full potential. As a counter example, Kerbal Space Program used to run its physics calculations on a single core and had no multithread support. No matter how many cores you had, you would get the same performance (assuming equal CPU clock speed but different CPU core count) SImilarly, limitations may apply to Stellaris' code which means that your hardware specs may be irrelevant to some degree.
    – Flater
    Commented Feb 12, 2020 at 1:22
  • 1
    @flater that's why i included this sentence : "Stellaris' godawful optimization". I really agree that hardware should be irrelevant to this question. It is well known that Stellaris has a long way to go in terms of optimization
    – tatsu
    Commented Feb 12, 2020 at 13:24

2 Answers 2


There's nothing you can do from a hardware perspective; you have a very good CPU for this (though it is quite old--consider upgrading soon!), which is where the performance bottleneck comes from; the devs as you know need to spend a lot of time optimizing the CPU calculations.

From a game-play perspective, your best bet is to only use certain play styles:

  • don't use slaves or visit the slave market.
  • optimize for pop unemployment rather than unfilled jobs.

Each tick, the game checks for unfilled jobs and tries to assign people or migrate pops to planets that need jobs. You will get lots of unrest, crime, etc. optimizing for pop unemployment instead, but it makes the game playable, at least.

For reference, I am able to play through year 2700+ on a large galaxy at a speed of about 1.5 game-days per second by playing with slavery disallowed and with all my planets having more pops than there are jobs available. My specs are:

  • Ryzen 5 3600X - stock
  • 32GB of DDR4 2133 RAM - stock
  • Samsung NVMe M.2 SSD
  • GeForce GTX 1060 6GB
  • And I play on borderless windowed fullscreen at 1920x1080 resolution with most video settings set to high or max. My population at this time is around 15,000 and I have a few hundred planets.
  • what's to stop the other AI players from using slaves / have unemployment? don't all players whether AI or human have sim calculations?
    – tatsu
    Commented Feb 12, 2020 at 18:39
  • Tongue in cheek answer: Hack your expectations instead of your computer. Play the "Star Trek: New Horizons" mod into the late game as it completely crushes your machine. When returning to vanilla Stellaris, you'll glory in the relative speed!
    – tjd
    Commented Feb 12, 2020 at 20:21
  • 1
    @tatsu Nothing is to stop it, unless you have a mod that lets you set what ethics/etc. that AI play as. However, in any game with AI, the size of and/or complexity of running your empire should be much greater than any of the AI empires in the game by mid- to late-game (unless perhaps you're playing on Grand Admiral difficulty). I didn't mention it on my answer, but in the game where I am in year 2700+, I control the entire galaxy save for two fallen empires and one remaining normal empire with maybe ~30 systems.
    – TylerH
    Commented Feb 12, 2020 at 20:33

I found this post with console commands for a performance boost, and below are a few other ideas

Drivers, Drivers, Drivers

Chances are if your pc is not working as well as it should, your drivers are out of date, so check for updates for those

it would also be a good idea to test with other graphically intensive games to see if the problem persists, or if it is a issue specific to this game

finally, go through your specs, and look up for each [¨Part name¨ lag in stellaris] to see if anyone has fixes

  • 1
    This appears to focus on lag regardless of save-game length and on the graphical aspect, but OP specifically wants to know about late-game performance that is restricted by CPU, not by the GPU.
    – TylerH
    Commented Feb 12, 2020 at 16:07
  • my bad. the reddit post in theory would still help though.
    – Evan
    Commented Feb 12, 2020 at 16:08
  • no it won't, I didn't specify, but I'm on linux (ubuntu) not windows. on linux all drivers are kept up to date via kernel which itself is replaced when updates are run which I run once per day. there are no manually installed drivers to worry about. the reddit post however is useful, thanks.
    – tatsu
    Commented Feb 12, 2020 at 18:42

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