Hi there iopser.
Could you post your PC specs here?
Hi there!!! Fate-is-one-edge
my pc is this one.....
those are my specs...
and with the last upate, no fix at all....
Hi again iopser!
My CPU is an AMD FX-8320, my GPU an AMD RX480, my RAM is 8GBs and my OS is Windows 8.1. Pro (64-bit).
I run the game on maximum settings, except AA (which I have turned off). Comparing with your pc specs and performance, I have to say that I encounter similar issues, when the population of the city is over 450-500 people. My lowest FPS is on the "Winterhome" scenario, while having approx. 500 population and the whole crater is filled with buildings and debris, hitting 20-25 FPS. Another occasion, where performance falls to 25-30 FPS is while playing with a fully expanded city in the main scenario ("A New Home") and a population of approx. 450 people, while the storm is raging.
I was curious as to why this is happening, as yourself are, and I found out that this is actually not an issue. Yes, it is not a bug, nor a glitch, rather the limitations of the game engine. I do remember the same question being asked to the developers, on a live Q&A over Twitch TV and the answer was that, initially they did not expect for the city to reach more than 400-500 population, so they build the engine around such expectations. Later down the development road, as things where added to the game, they took the liberty to allow the player to exceed the 400 population mark, but driving the engine to its limits, which means suffering from severe performance penalties. Now, the population is not only the number of people rendered on the screen, but also their routines (sleeping, moving to work/to eat, getting sick, patrol, e.t.c.) and the time and order, each of their actions takes place, individually. So the engine has to keep tabs on where they show on the screen (rendering), but as well as where they "show" up on the economy tab (logistics of routines), with the second being one of the most CPU intensive procedures of the engine.
Could they rewrite parts of the engine? Maybe, but it would mean also redoing time consuming work, already completed on the engine's previous build. Could they plan ahead with greater expectations? Maybe, but the 400 population mark was apparently already ambitious. Could they optimize some aspects of the game engine better? They did, as mentioned in patch notes, but there is so much that can be done without having to "remake" the whole game.
In cases like ours, the best thing that can be done, is either turning down CPU intensive video settings and background applications, or upgrading our CPUs to compensate for the "overdrived" engine. Personally, considering its single player, strategic nature, I can make my peace with late game FPS dips, without much annoyance. I wish we could reach a stable 60 FPS performance on this game, but I hope I helped you understand why this cannot happen without some drastic changes, either to the game engine or our CPUs.
P.S.; WIndows 10 are known to cause performance issues with games (potentially "robbing" you of those 5-10 precious extra FPS), after installing new updates, so be sure to check that out with someone who runs Windows 10 as well.