Population Soft Caps With Performance

[Sheepie]

Cities skylines 2 has no citizen cap, meaning that so long as your city keeps growing, it has to keep simulating more and more and more citizens, which takes a toll on even cutting edge PCS. For those who have gotten pretty far into the game, what population did you get to before experiencing some and major performance issues?

I have a RTX 4060 Ti and a Intel Core I7 13th Gen Processor. I began experiencing some slowdown at 200k population, and now at 225k I'm seeing frequent slowdowns and hiccups. Also my poor computer is starting to sound like a jet engine trying to simulate all those people.

Let me know what you have and what you've been able to achieve before experiencing issues too. :)

[Apop85]

I have a AMD Ryzen 7 5800X octacore and an RTX4070Ti 12GB as well as 64GB of DDR4

I started to feel the impact on the simulation speed at around 150k inhabitants. When my city was "finished" at about 360k inhabitants, the simulation speed was around 10-20% speed and also got stuck from time to time. In terms of FPS, however, everything always ran smoothly.
https://steamcommunity.com/sharedfiles/filedetails/?id=3079911231

[Stealthy]

Worth remembering that traffic affects this a lot. Lot of queues and poor traffic flow causes more calculations to be done for alternate path finding and that consumes CPU power. Less need for this, better overall performance.

Typical slowdowns seem to happen around peak rush hours when traffic is worst.

[Apop85]

Originally posted by Stealthy:

Worth remembering that traffic affects this a lot. Lot of queues and poor traffic flow causes more calculations to be done for alternate path finding and that consumes CPU power. Less need for this, better overall performance.

Typical slowdowns seem to happen around peak rush hours when traffic is worst.

Traffic in my case was good.. Maybe a little jam in the morning and in the eventing but nothing to worry about. Public transport on the other side... I carried about 400k citizens per month and you really felt it if you get too close to one of those transit stops with the camera 😂 multiple tousands of people waiting for bus/tram/subway. So i think public transport had a heavier impact on performance at least in my city.

[notreal]

Originally posted by Stealthy:

Worth remembering that traffic affects this a lot. Lot of queues and poor traffic flow causes more calculations to be done for alternate path finding and that consumes CPU power. Less need for this, better overall performance.

Typical slowdowns seem to happen around peak rush hours when traffic is worst.

its related to pathfinding, but Im not sure its just traffic itself. As in a city, basically same simulation speed with traffic and after clearning traffic.

What makes most difference are densities- high density you can have 2x more population and it will lag less than half the population but only low density.

[cpmcjr]

14900k and an rtx 4080, not sure when the slow down started, but currently at 977k population and the game is snail slow. Like, make a couple changes or build some new things than I need to wait an hour to see the effects.

[Rdizz]

https://steamcommunity.com/app/949230/discussions/0/3877095833488828718/

[zaltocleotl[Banned@Paradox]]

There is a population cap, and it's a hard limit. A high one, but still a cap.
Colossal Order, in their infinate game-creator wisdom, made the game compatible only with 64-bit systems. But then, they only used 32-bit integer registers, meaning they limited the ability of calcualtions to 32-bit integers, which is a hard limit of 2,147,483,648. If any calculation exceeds that number, it will be ignored, limited to 2,147,483,648, or cause a crash.
They could have used int64, with a limit of 18,446,744,073,709,551,615.
But why?
Because calculating while limited to 32-bit integers means the game will have to calculate twice if any number or the total of the calculation is over 2,147,483,648. Not to mention the limitation of 32-bit over 64-bit anyway.
So why make the game playable only on 64-bit?
The engine demands it. That's all. Even if you don't use 64-bit integers.
So they could have done a simple 'find and replace' to get rid of int32 calls, or they could have just programmed from the beginning. But they changed engines about 2/3 of the way through development. Brilliant.

[Apop85]

Originally posted by zaltocleotl:

So why make the game playable only on 64-bit?

To use more than 4GB of RAM which is the limit of 32 bit applications? Don't know why you bother about. Do you still use a 32 bit system? Then why should you use a 2^64 limit on a property like cims where most modern computers struggle to handle the workload of ~200k?

[Major Kudos™]

Mine started to get slow at 300K very slow at 500K stupid slow at 600K insanely slow at 700K WTF slow at 800K and NASA stellar photography slow at 900K

But we press on regardless!
https://steamcommunity.com/app/949230/discussions/0/3877095833488828718/

[Major Kudos™]

Originally posted by Rdizz:

https://steamcommunity.com/app/949230/discussions/0/3877095833488828718/

Opps did not notice you already posted this, Thanks for that.

[Major Kudos™]

Originally posted by cpmcjr:

14900k and an rtx 4080, not sure when the slow down started, but currently at 977k population and the game is snail slow. Like, make a couple changes or build some new things than I need to wait an hour to see the effects.

Finally someone who shares my pain! please supply some screenshots showing pop data and happiness. It would be a great help for us trying to do same.

[Cosmic Sea]

Originally posted by zaltocleotl:

There is a population cap, and it's a hard limit. A high one, but still a cap.
Colossal Order, in their infinate game-creator wisdom, made the game compatible only with 64-bit systems. But then, they only used 32-bit integer registers, meaning they limited the ability of calcualtions to 32-bit integers, which is a hard limit of 2,147,483,648. If any calculation exceeds that number, it will be ignored, limited to 2,147,483,648, or cause a crash.
They could have used int64, with a limit of 18,446,744,073,709,551,615.
But why?
Because calculating while limited to 32-bit integers means the game will have to calculate twice if any number or the total of the calculation is over 2,147,483,648. Not to mention the limitation of 32-bit over 64-bit anyway.
So why make the game playable only on 64-bit?
The engine demands it. That's all. Even if you don't use 64-bit integers.
So they could have done a simple 'find and replace' to get rid of int32 calls, or they could have just programmed from the beginning. But they changed engines about 2/3 of the way through development. Brilliant.

We don't need more than 2 billion citizens. Not to mention, without having a look at the code, I don't think anyone has confirmed the data type used for citizen count. Regardless, 32 bit is fine. The reason they use int instead of a larger data type is to conserve memory. Regardless, the game runs horrendously slow after 300k+ pop, so forget about 10 million, much less a billion or even two billion citizens. The datatype/int max value isn't even the issue.

[zaltocleotl[Banned@Paradox]]

Originally posted by Apop85:

Originally posted by zaltocleotl:

So why make the game playable only on 64-bit?

To use more than 4GB of RAM which is the limit of 32 bit applications? Don't know why you bother about. Do you still use a 32 bit system? Then why should you use a 2^64 limit on a property like cims where most modern computers struggle to handle the workload of ~200k?

Except this was fixed years ago with page-map swapping. 32-bit programs can easily access all RAM up to the current 64-bit limit through the OS. It is hardwired into Windows 8.1 and later OS as well as Linux who also can re-map 16-bit apps memory as well.
The program has to be told the re-mapping is being done so it can re-map addresses accurately, and that is basically a plug-in less than 1MB in size.
The real reason CO used 64-bit and made it absolutely mandatory was to keep the bandwidth between the GPU, RAM and CPU as wide open as possible. On a 32-bit system, this game would not run even one-tenth as fast and the graphics would be impossible.
In fact, this might be one of the very first games ever to take advantage of PCIe 4. If CO wants to do the work, they could. The game could theoretically benefit so much from PCIe4 that it would be worth the work to do it.

[Rdizz]

Originally posted by zaltocleotl:

There is a population cap, and it's a hard limit. A high one, but still a cap.
Colossal Order, in their infinate game-creator wisdom, made the game compatible only with 64-bit systems. But then, they only used 32-bit integer registers, meaning they limited the ability of calcualtions to 32-bit integers, which is a hard limit of 2,147,483,648. If any calculation exceeds that number, it will be ignored, limited to 2,147,483,648, or cause a crash.
They could have used int64, with a limit of 18,446,744,073,709,551,615.
But why?
Because calculating while limited to 32-bit integers means the game will have to calculate twice if any number or the total of the calculation is over 2,147,483,648. Not to mention the limitation of 32-bit over 64-bit anyway.
So why make the game playable only on 64-bit?
The engine demands it. That's all. Even if you don't use 64-bit integers.
So they could have done a simple 'find and replace' to get rid of int32 calls, or they could have just programmed from the beginning. But they changed engines about 2/3 of the way through development. Brilliant.

Id assume they figured no ones computer could actually get to those numbers is why.

[digi83]

Originally posted by Apop85:

I have a AMD Ryzen 7 5800X octacore and an RTX4070Ti 12GB as well as 64GB of DDR5

I started to feel the impact on the simulation speed at around 150k inhabitants. When my city was "finished" at about 360k inhabitants, the simulation speed was around 10-20% speed and also got stuck from time to time. In terms of FPS, however, everything always ran smoothly.
https://steamcommunity.com/sharedfiles/filedetails/?id=3079911231

You have a ddr5 on a 5800x? I highly doubt that, you have ddr4