Cities: Skylines II is implemented using the Unity game engine. The most recent patch to the CS2 program uses low-level, optimized code features that causes some CPU cores [especially Core i9-14900K] to branch into a failure path resulting in what is known as a crash to desktop. If the program is allowed to operate across all cores, one or two of the performance cores may cause a fault. Prior to the BIOS update [Intel 0x12b fix] when P-core 4 and 5 were manually disabled, the browsers did not exhibit tab faults - whatever was causing these faults may still crash CS2. Also, [prior to the BIOS update] when Software Protection [sppsvc.exe] was allowed to run on P-cores 4 and 5, a blue screen [Windows 11] OS crash would result.
The test system is a recent Core i9-14900K 24-core [32 logical processors] with the latest BIOS and a 4080 GPU. I have been successful in minimizing the more frequent crashing in the latest CS2 patch [1.2.0f1] by setting the 'Cities2.exe' process affinity to avoid using P-cores 4 & 5 [plus their logical pair 12 & 13]. I was able to build a stable-running city with a population of 1.2 million. Here is the advanced command string in my launch properties:
C:\Windows\System32\cmd.exe /c start /affinity ffffcfcf "C:\Program Files (x86)\Steam\steamapps\common\Cities Skylines II\Cities2.exe" %command%
Of course, the affinity mask can be customized. [YMMV]
