Identify what's slowing down your progress in Cities: Skylines.
Identify what's slowing down your progress in Cities: Skylines.
Cities Skylines relies heavily on draw calls, meaning many objects need rendering. Your main limitation comes from a single core being pushed to its limit because of DX11. Core usage isn't precise, but checking Process Explorer will show one thread using 25% on a 4-core processor and 12.5% on an 8-core setup. This indicates the bottleneck is that core.
Your city was quite spacious at first, but performance started to lag noticeably after reaching around 200,000 people. At that point, even with a mid-range processor like the i5-6600K and a decent graphics card, frame rates dropped significantly in crowded areas. The situation worsened further if you were using higher settings or running more demanding applications. I’m not sure how much an i7 would help, since I haven’t seen clear comparisons that confirm it.