Sudden Performance drop / standstill (Specific City Tile with NAM lite or NAM Full installed)

[corint 16]

**Edited to include the following to save the reader time: After submitting the post I realized that I should mention this in advance in an effort to save readers time from reading the entire post. This speed reduction/standstill seems to occur on a specific fully occupied large city tile and does not occur on the other medium/small city tiles in the same region. Is it possible that a city file could become corrupted to a point that the corruption/performance hit is only noticeable when this specific city tile is played in conjunction with the NAM plugin?**

I do appreciate the work/effort everyone here does and I hate to point towards NAM being the potential cause. I could be wrong and hopefully am wrong as mentioned above this could all be potentially due to a Corrupted City Tile and not NAM at all.

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Original Post:

Hi All, for some reason with NAM Full or NAM Lite plugin installed I have continued to experience very slow performance and sometimes a total standstill during in game play. I do have the game installed and played in steam. The plugin is installed in the normal documents/SimCity 4/plugins folder. I play the game set with all the performance recommendations, graphics list, critical mods to install and AMD Radeon Settings per post:

 

And to be sure that I didn't forget to do something I have even followed the step by step instructions per Ulisse Wolf's most recent video which I really appreciate and I thank him and everyone here at Simtropolis for their efforts in making the game enjoyable:

During my various troubleshooting steps I have even ran the game with no plugins installed, sometimes with just maxis buildings plugins installed then with NAM installed or only with NAM installed to troubleshoot. I have even tried adjusting the steam launch options tweaks and still the same. I even have the correct ini texts edited, the plugins fix, the 4gb patch, everything known to us, all types of Radeon settings combinations.

But despite my various efforts to correct these issues it does seem to be NAM related. Overtime I have done every type of performance combinations and none of them seem to help. Game works fine and fast without the NAM Lite or NAM Full installed. Once NAM is installed performance drops significantly sporadically throughout the in game months.One thing I will add and not sure if this makes any sense to somebody but for some reason the performance drop/pause becomes very noticeable during the specific months of April, August & November (not sure if this means anything or helps). The game/days will slow down and then completely stops to a complete standstill no matter what the speed is set too (turtle rhino cheetah i believe are the play speeds). Sometimes it takes almost 5 minutes for the dates to start cycling again just to have it slow down and stop all over again a few short months later.

Has anyone else experienced anything like this before? Are there any type of NAM settings/adjustments that I can make that may help with this? Again I always use NAM lite and never change the default settings keeping them at lowest recommendations. But it doesn't matter what NAM Settings I put with NAM Lite or NAM Full install it continues to happen. Side note: I am very thankful to the Simtropolis Community and appreciate everything everyone does. I have played this game since it's release date and have even been a simtropolis subscriber since 2009. I have used many versions of NAM in the past but more specifically (recently last 4 years) with NAM version (45?) 46, 47, 48.

I do appreciate the work/effort everyone here does and I hate to point towards NAM being the potential cause. I could be wrong and hopefully am wrong as mentioned above this could all be potentially due to a Corrupted City Tile and not NAM at all. Any help is greatly appreciated.

[Lucario Boricua 7,048]

That performance drop is expected, as it's caused by the game's traffic simulator algorithm using the NAM traffic simulator parameters. The game alternates between small / simple simulation runs whenever the game month changes and every 4 months it runs a rigorous simulation. As the parameters we programmed into it favor efficient routes in terms of time rather than physical directness, the algorithm expends more computing power optimizing the routes. This slow-down is normal, and is present in all NAM variants unless you specifically remove the traffic simulator files from the game.

[corint 16]

Hi Lucario, Thank you very much for responding your efforts and help is greatly appreciated. I noticed you were also in the video with Ulisse Wolf. That makes person sense as it occurs on specific months. I assume removing the traffic simulator might have an negative impact on how NAM performs? Just asking although I am going to keep everything as is.

 

Thank you very much to you, Ulisse and the rest of the Simtropolis and NAM team for making the game great and enjoyable. Much Appreciated.

[Lucario Boricua 7,048]

Yes, the Network Addon Mod does depend on the Traffic Simulator to work in the best way. Here are some ways in which the mod depends on our programming:

• Higher capacity and higher speed networks would be grossly underutilized if we kept the game's default traffic simulator parameters. No point in having your RealHighway or your Hybrid Railway if it gets a handful of passengers while your direct street from the suburbs to the downtown offices is at a standstill traffic-wise. With NAM 45, we modified the traffic simulator files to generate a stronger congestion effect when decreasing speed as the networks get more traffic. This effect really helps re-route sims into high-speed and high-capacity networks, making them get a level of use that's more consistent with their relative importance in your cities.
   
• The traffic simulator changes the programming of intersection congestion, such that network cells whose paths behave like an intersection actually have a small capacity boost (25% over the nominal capacity). We actually need this functionality to increase the capacity of certain road networks, through special invalid paths that trick the game into treating the cell as an intersection. These are the distilled intersection paths (DIPs) and the crossover paths (allow lane-changing between network cells going in the same direction). Without this programming, these networks would have less capacity than the networks with normal paths. We use this effect to also support the FLEX turning lanes (FTLs) and I'm working on adding them to roundabouts, to make these intersection pieces enhance traffic compared to plain intersections.
   
• The more rigorous calculation of commute routes helps sims get better matched to the appropriate jobs, which results in more prosperous cities that grow more population, have a higher share of wealthy residents, and are more resistant to dilapidation and abandonment.
   
• Walking was made faster compared to the game's default, such that sims are more encouraged to start / finish trips using transit services. With the default waking speed, the sims would end up underutilizing bus and rail services to move around.
   
• The traffic simulator increases the capacity and speed of the Dirt Road network to be similar to the Maxis Highway, that's necessary to make the RealHighway Mod work. Otherwise this capacity would be between those of street and road networks, which wouldn't make for a convenient driving experience.

[corint 16]

Wow I don't know how you guys do it. And sorry I didn't mean for you to explain in detail, but thank you it is much appreciated. Your details and explanation helps educate not only me but  other gamer's too in understanding how the game and plugins in function. And that is what makes this website and community great. The game runs better with NAM installed and it is "an essential must have for the game".

Thanks Again Lucario and Team for the excellent work!

[corint 16]

Hi Simtropolis NAM Team,

Just a quick follow up question to this. And I apologize in advance for rehashing this subject and only bring it up again as I am Attached to this CITY A current playthrough as I put more time and effort into it and would hope to keep using this city hopefully without the performance issue. I hope you understand. To try and make this as simple as possible I have two cities.

1. City A Current Playthrough smaller population city Large City Tile - With sudden slow Performance drop/Standstill Issue.
2. City B Previous Playthrough larger population city Large City Tile  -  Without sudden slow Performance drop/standstill issue.

 

-Both Cities use the exact same x86Steam Installation File Folder and the same My Documents SimCity 4 File Folder which inside contains folders:

• HTTPCache
• Plugins (w NAM Version 48 Lite installed)
• London Region Map
• SimCity 4.cfg.

All I am doing is cutting/pasting overwriting City B to City A in the London Region Map File Folder. I hope that makes sense.

My Questions are:

1. Why would the performance issue only occur in one city City A and not in City B with them using all the same identical files and folders NAM48 Lite Included? 
2. Maybe City A is corrupted from a save on quit error or something and doesn't play nice with NAM for some reason?
3. Maybe there is something I can do to correct this issue?

Any thoughts or feedback is greatly appreciated as always.

[Lucario Boricua 7,048]

Can you show us screenshots of the city? Wondering if there's something more to the lag than the city size or the save file being corrupted somehow.

[DayneTreader 0]

I have also discovered a performance drop, which I believe is connected to the 4GB patch. Whenever I zoom in or out the city has to re-render.

[Null 45 3,086]

16 minutes ago, DayneTreader said:

Whenever I zoom in or out the city has to re-render.

That is standard game behavior. The 4GB patch shouldn't have any effect on that, all it does is let SC4 use more RAM. The number of plugins you're using likely would affect the scrolling and zoom performance, as SC4 may have to fetch models and textures from disk when it re-renders.

[corint 16]

Hi Lucario, Attached are the screenshots of the city. Let me know if these help or if you need anything else. One weird thing I can say is that the game save is Year 124 and the performance/standstill issue doesn't occur until year 126 and continues to happen every year after that.

And you may be onto something. When I either dezone or bulldoze the whole city the problem goes away completely. Thank you for continuing to help I appreciate it. 

[corint 16]

Hi Lucario & Team, I am not sure if this is possible but maybe I could send/share my city tile (I have never shared before so I am not sure how). I started a new city and it seems to be happening again so I'm not sure if sending the file will be of help. Thank You in Advance.

[rsc204 21,857]

Honestly there really isn't any point in sharing your city since the problem is really quite clear, the short answer being nothing is actually wrong.

SimCity 4 is over 20 years old and the technology/code that it runs on dates to a long time before release. Slow down will generally speaking always eventually occur at the point where the game is doing more than your CPU can handle. This is more common in large city tiles and with larger populations, certainly 500k is more than enough. Likewise the more models (buildings and props) you have, the more work the game needs to do when scrolling and zooming especially. The NAM adds quite a lot of content, depending on your install, if the Lite version is slowing performance that's not typical, but the Full NAM Install/Controller again gives the game a lot more to do.

The best anyone can do is ensure their game is setup for the best performance possible, which basically entails:

• Ensure you have the 4GB Patch installed and that your computer has 4GB of free RAM/memory available
• Run SC4 and your Plugins from an SSD drive, Hard Drives are a huge performance bottleneck
• (Not related to your problem): Use Hardware DirectX rendering and if necessary a Wrapper for modern hardware that doesn't natively support DirectX9

Once you've ticked all of those off, you are at the mercy of how much your game has to do. Those moments where the game freezes are generally when the game is under strain and the Commute simulator kicks in, it runs every 3 game months. To explain why is simple, it's the exponential increase in the amount of processing (math) needed to find everyone a path from their homes to their jobs. Actually, approximately 50% of your sims work, so if you have 500k sims, that means the game needs to compute paths for 250k sims every three months. Again there isn't a specific figure (# sims) that will cause slowdown for everyone, it's a gradual build up and once more is influenced by a number of factors combined. How many mods you have, what those mods do, how many sims exist and how many objects are being displayed and lastly how fast your CPU can do math. But inevitably regardless of your system, poor performance will eventually result. So when the game pauses for breath, it's because it can no longer do all the calculations needed in real time, in other words the game has to wait for the results to be processed before it can continue.

This isn't helped by the fact that SC4 is ancient code from another era in computing, which in real terms means that SC4 can not harness a fraction of the potential power of a modern PC.

[Lucario Boricua 7,048]

@corint Looking at your screenshots, this is an impressively big city! With half a million inhabitants with large suburban areas, it's no wonder the game performs sluggishly. In addition to the recommendations from rsc204, another thing you can use to speed up your game is the Startup Performance Optimization DLL, courtesy of @Null 45, this one changes how the game loads its files, speeding up the loading time of the game, first city and first menu considerably!

 

[corint 16]

Hi Lucario, Thank you for the response and suggestion and taking the time to help out. I unfortunately have those included.Here are the screenshots.Thank you for all your efforts. I will just sum this up as an anomaly or something. Thanks again.

[corint 16]

Oh and just for you to see I also attached a screenshot of the other city which is much bigger in population isn't effected at all. And all i did was cut and paste the Region File Folder in Documents - SimCity 4 File Folder for this other city. Maybe save file issue also. Thanks Lucario and take care.

[Null 45 3,086]

42 minutes ago, corint said:

Here are the screenshots.

Your Startup Performance Optimization DLL is outdated.

[corint 16]

On 2/23/2025 at 1:48 PM, Null 45 said:

Your Startup Performance Optimization DLL is outdated.

Thank you Null.

[corint 16]

Thank you for your responses rsc204, Null 45, Lucario Boricua and again thank you for all the work Simtropolis and NAM put into the game. Much appreciated.

[bob.blunderton 47]

I noticed a serious slowdown related to the airport at some point.  Not sure if it still does it, but it was especially evident when I first installed the NAM update and began playing again.  Bulldozing the airport and sometimes even rebuilding it right away or not rebuilding it helped fix it (which the city 'used' but didn't seem to recognize because it kept asking 'mayor getting the business about airport' or 'business clamor for airport glamour' notes on the message feed thing).  Leads me to believe since it doesn't do it, it was an artifact of not removing all the old NAM files prior to upgrading.  Was a miracle it worked at all.

I know for the other user, this is likely solved; but I just wanted to throw that out there in-case someone gets a serious case of slowdown!  This is a non-issue over here these days as I've double-checked and haven't had it in the last 2~3 days.

Now if I could just get the Tulep puzzle pieces from the old version (for one way roads, roads, avenues etc), I'd be alright.  They aren't there (neither is the menu button) any more.  Got it back!