The newer Steam "643" build broke some plugin compatibility with older B.A.T. models (buildings). The GOG version remains the purest 1.1.641 experience. If you own the EA App version... good luck. You will likely need to extract the 1.1.641 .exe from a backup. When Maxis closed and EA left SC4 to rot, the community did not. They took the 1.1.641 executable and turned it into a foundation. Every high-resolution city you see on Reddit r/simcity4—the realistic ports, the custom interchanges, the 10-million-simoleon regions—all of it is powered, silently, by that specific version number.
It isn't just a patch. It is a symbol of modding resilience. simcity 4 1.1.641
Download the 4GB_Patch.exe (made by NTCore). Run it, select your SimCity 4.exe (version 1.1.641). It will modify the executable header to accept 4GB of RAM. Backup your .exe first. The newer Steam "643" build broke some plugin
Download NAM 47 or 48 (full installer). Run it. Because you have 1.1.641, you can select "Controller Compiler" and "Traffic Simulator Configuration" with confidence. The .exe will not reject the complex pathfinding. If you own the EA App version