Cities: Skylines is a deep city-building simulation where you zone land, construct roads, manage traffic, and balance services for growing populations that can reach hundreds of thousands of simulated citizens. Most players spend long, creative sessions expanding districts, experimenting with traffic layouts, and layering mods from the Steam Workshop that add custom buildings, props, and gameplay mechanics. These sessions often involve rapid camera movement across the map, placing intricate infrastructure, and tweaking policies in real time. High-FPS performance in this game matters because the simulation runs on the same thread pool that drives frame delivery. When your city grows dense, citizen pathfinding, service dispatching, and traffic calculations can create sudden CPU spikes that cause stuttering, delayed UI responses, and hitchy camera panning. Unlike shooters where raw frame rate is the main goal, here the priority is consistent frame pacing and smoothness so that building tools feel precise and responsive rather than fighting against simulation lag. Mods dramatically increase the load by adding more assets and calculations, making RAM capacity and fast storage essential to prevent crashes or long loading hitches. Common pain points include cities that run at acceptable average speeds but suffer noticeable micro-stutters during peak activity, or setups that feel fine with vanilla play but crumble once popular visual and gameplay mods are enabled. Many players mistakenly focus only on GPU power, not realizing the CPU and memory subsystem determine how stable the simulation stays at high refresh rates. Before choosing hardware, understand that this scenario demands a CPU with excellent cache and multi-core efficiency paired with fast RAM to keep both the simulation speed and frame delivery smooth, rather than simply chasing the highest possible frame counter.