SimCity 4 memory limit and plugins

[QuantumChicken 82]

Hey, I am curious, I am at almost 4GB of plugins, does that equate to 4GB memory? Or can I add many more plugins before I hit that limit?

[rivit 3,391]

SC4 doesn't really use the 4GB all at once but it's been seen to use up to 2.8GB in a big city - the place to look is in TaskManager (Win) or its equivalent on other platforms - then you can see what resources it directly uses. It will use 1 CPU fully (its CPU bound), but doesn't usually trouble the modern addon GPU, although older integrated ones can struggle.

SC4 the exe takes about 600MB, it manages a memory cache of nominally 1.2GB and seems to find ways to use up to 2.8GB for itself. Anything that's not directly needed stays on disk until it is. The operating system will utilise what it can of what's left for tasks and disk cache.

SC4 scans through all plugins twice at startup to find out what it's got to work with, and does a gather of resources, many from disk, on opening a city. Every change of view or zoom can require resources from the cache (or disk if its full). Because the cache is pretty smart it finds ways of keeping its memory use down - it was built in a time that 2GB was the limit on the machine. However it has been shown that to process the full NAM controller (its several times larger than the original SC4 one) we need more than 2GB. If you have oodles of memory the OS will keep used files in memory disk cache too. 

Now about half the entries in SC4 files are textures and they are generally compressed by more than 60% in the .dat files. Eventually textures are uncompressed in main memory or GPU memory. The more hi-def textures you use (terrain, buildings, props, automata) the faster that the cache is used or paging starts. HiDef is typically 4x as large as standard def. Most other items in SC4 (other than sound or animation) are actually relatively small - there's just lots of them.

However you will find that only as few as 40% of the textures in your plugins actually get used unless you have every lot that the megapacks service or use a lot of different network pieces in one city so this cuts the load down a lot.

Without looking at Taskmanager or watching the disk light for paging you can't easily tell where the plugin limit is - for everyone it will be different. But the smaller the set, the faster it will load and the smoother it will run, all else being equal.

[CorinaMarie 29,605]

@KillrChicken

Check out the Plugin folder size: 2019 Edition (and beyond) topic for some insights of what works for other peeps. That is the new version of the older topic: What's the size of your plugins folder?

[QuantumChicken 82]

Thank you both for the insights. Very helpful. I am used to Cities Skylines method of using memory and its 64-bit binaries.

[Ulisse Wolf 4,412]

We do not yet know when we reach the limit. Generally when you use too many mods the game can get slow. I recommend datpacking to drastically reduce loading times

Check this tutorial and this video