Cities Skylines 2 - Map: Sweeping Plains (4x)
146I've reached a population of 500k. Although it has slowed down, it's not unmanageable, and I believe it's possible to reach 600k.
However, if you're aiming to play without stress, I'd say 400k is a comfortable population limit with an AMD R9 5900x. Of course, with a better CPU, it should be possible to manage even higher populations with ease.
Compared to the early release, where the game would start crawling at 100k and become almost impossible to play at 200k, the performance seems to have improved by at least 3 times. And I think there is still room for further optimization.
Now, the main issue... let's start by cursing at C-BAL, ㅎ_ㅎ.
* The biggest obstacle to population growth was parks. When there are parks, population influx doesn't happen properly. Moreover, once you remove parks, the population ratio seems to stabilize.
* Most of the statistics are meaningless and a mess. RCI indicators don't hold any significance, and you have to grow the city based on intuition. Starting with the resource stats, most metrics are a mess.
* The service availability indicators for city services are fake. You need to manually observe the city and adjust or add more services accordingly.
* It's recommended to set up public transportation to cover a sufficiently large area.
* Sometimes, just restarting the game results in noticeable improvements, and this trend is more pronounced as the population grows.
* There's one strange phenomenon: commercial and office zones need to be mixed in the same area. This could be a bug or not, but mixed areas seem to reduce office demand.
Conclusion: You created an underground economy and call this "Economy 2.0"? It feels more like you've destroyed the economy. When will this beta test finally end? ... Even though it has become an underground economy, the game is still running somehow, so if you just ignore the various statistics and enjoy the game, there doesn't seem to be a big problem.