Trying to make SimCity 4 run on graphics card

[Pepe The Great 227]

Hello all

I am trying to play SimCity 4 on my latest hardware, a Radeon RX 6800 XT. I followed the steps to edit the "Graphics Rules" and "Video Cards" files, but I am unsure if I have done it correctly. Since after I loaded into the game, I didn't recognize any changes; the game's fps is low but playable.  It would be nice if the community could look at my changes and indicate if I have done them correctly.

Thanks.

[rsc204 21,808]

The information entered looks right to me, but the only way to be sure is to look at the log file the game creates, which will show us exactly what is detected and which settings are in use. To find this, open the Install DIR for SC4, then the Apps subfolder, a .txt file with YOURCOMPUTERNAME-config-log should be here. Copy/Paste the contents of this file into a follow up post and we'll have more information to work with.

As you have a Radeon card, there are known issues with them auto-detecting the best settings for use with SC4. So the first step is ensuring that FastCard is active, although you can avoid having to work all this out yourself if you use this application.

Looking at the download for SC4Launcher by LogicBomb, the following may be applicable to you:

Quote

The 'Force Draw On Scroll Fix' fixes a compatibility issue that exists between SC4 and AMD cards, the fix utilizes the 'Graphics Rules.sgr' file in order to force SC4 to draw details when scrolling, regardless of AMD/ATI hardware.

In theory you could achieve the same thing by modifying the Graphics Rules.sgr file, but honestly I can find no information as to what actually needs modifying, but if you are having issues you could try using this App/Setting. :update: It turns out it simply directs the scripts to alter the dirtyrectmergeframes value from 2 (fast card) to 4 bypassing the FastCard profile in the process.

Lastly, for brand new GPUs and many older ones too, it's becoming almost mandatory to use a Wrapper of some kind if you want good performance. As technology moves on, support for legacy standards gets dropped and being an old game, SC4 needs your hardware to have legacy support. Wrappers basically sit in the middle between the game/driver and convert calls/code between the modern version of DirectX your machine supports and the legacy DX functions SC4 needs.

[Pepe The Great 227]

7 hours ago, rsc204 said:

The information entered looks right to me, but the only way to be sure is to look at the log file the game creates, which will show us exactly what is detected and which settings are in use. To find this, open the Install DIR for SC4, then the Apps subfolder, a .txt file with YOURCOMPUTERNAME-config-log should be here. Copy/Paste the contents of this file into a follow up post and we'll have more information to work with.

As you have a Radeon card, there are known issues with them auto-detecting the best settings for use with SC4. So the first step is ensuring that FastCard is active, although you can avoid having to work all this out yourself if you use this application.

Looking at the download for SC4Launcher by LogicBomb, the following may be applicable to you:

In theory you could achieve the same thing by modifying the Graphics Rules.sgr file, but honestly I can find no information as to what actually needs modifying, but if you are having issues you could try using this App/Setting. :update: It turns out it simply directs the scripts to alter the dirtyrectmergeframes value from 2 (fast card) to 4 bypassing the FastCard profile in the process.

Lastly, for brand new GPUs and many older ones too, it's becoming almost mandatory to use a Wrapper of some kind if you want good performance. As technology moves on, support for legacy standards gets dropped and being an old game, SC4 needs your hardware to have legacy support. Wrappers basically sit in the middle between the game/driver and convert calls/code between the modern version of DirectX your machine supports and the legacy DX functions SC4 needs.

Hello, thanks for the reply, please see below for my game log.

Quote

 

Log generated on 1/29/2023, 00:19

Flags
-----
hardwareDriver = true
DXT = true
fullscreen = true
MMX = true
FPU = true
backingStore = true
forcedFSAA = false

Strings
-------
userName = fdjw8
appName = SimCity 4
version = 1.1.641.0
osVersion = Windows NT 6.2
computerName = DESKTOP-UGBBS76
CPU = AuthenticAMD
sglDriverName = DirectX
sglDriverVersion = 2.0
driverName = aticfx32.dll
driverVersion = 31.0.12029.10015, GUID: D7B71EE2-30FF-11CF-F97B-02726EC2CD35
cardName = AMD Radeon RX 6800 XT
cardVersion = Vendor: 1002, Device: 73bf, Board: 52021849, Chipset: 00c1
cardIdentity = ATI, Radeon RX 6800 XT
soundDriverName = 
soundCardName = Primary Sound Driver
buildType = Release

Numbers
-------
cpuSpeed = 3693
memory = 4096
freeMemory = 4096
screenWidth = 2560
screenHeight = 1440
screenBPP = 16
videoMemory = 800
textureMemory = 800
textureStages = 8
bogoFPS = 0
bogoMPPS = 0

Rules
-----
applying Sound
applying high sound detail
applying City Detail and Day/Night Settings
applying low computer power>
applying high computer power
  option 9 = 3
  option 13 = 1
  option 15 = 3
applying Texture Quality and Building Variety Settings
applying low memory>
applying high memory
  option 3 = 3
  option 14 = 3
applying Variable Speed Automata
applying default
  option 10 = 1
applying Standard hardware
  option 0 = 1
  option 1 = 1
  option 2 = 1
  option 4 = 0
  option 5 = 1
  option 8 = 1
  option 7 = 1
  option 6 = 1
  option 11 = 0
  option 12 = 0
applying Standard hardware>
  option 1 = 2
applying Standard hardware>>
  option 0 = 2
applying Standard hardware>>>
  option 2 = 2
applying Standard hardware>>>>
  option 4 = 1
applying Standard hardware>>>>>
  option 11 = 1
applying Two stages
applying Lotsa vidmem
applying Radeon
applying Not Slow GeForce

Options
-------
Visual Effects       current:   2 recommended:   2
Cars/Sims            current:   2 recommended:   2
Shadows              current:   2 recommended:   2
Atmospheric effects  current:   1 recommended:   1
Water effects        current:   1 recommended:   1
Software/Hardware    current:   1 recommended:   1
Cursor               current:   1 recommended:   1
VariableSpeedAutomata current:   1 recommended:   1
Translucent UI       current:   1 recommended:   1
Graphic Detail       current:   3 recommended:   3
Building Load Speed  current:   3 recommended:   3
Texture Quality      current:   3 recommended:   3

Properties
-------
forcesoftwaredriver = false
renderdynamicview = true
renderstaticview = true
renderwatereffects = true
rendercloudsandfog = true
forcepointsampling = false
forcebilinear = false
forcenoalphablend = false
forcenoalphatest = false
rendershadows = true
renderdecals = true
usesecondstage = true
forcedebugtexture = false
renderparticleeffects = true
renderflorashadows = true
renderterrain = true
showupdateregions = false
usecursoreffects = true
drawlottextures = true
drawlotfoundations = true
drawlotwalls = true
forcetexturerepeat = false
usescreenshake = true
renderui = true
useupdaterectclipping = true
usevertexbuffers = true
showboundingboxes = false
useoverlayculling = true
rendersnapshot = false
noaddsigned = false
nopartialbackingstorecopies = false
usescreenflash = true
renderautomata = true
preferopaque = false
displayalertborders = true
drawlotopaquetextures = true
useviewcleanup = false
doautozoomandrotationchanges = true

viewoffsety = 0
viewoffsetx = 0
texturebits = 32
lodoffset = 0
shadowdebug = 0
maxparticlestarget = 10000
particlelodoffset = 0
effectprioritylevel = 5
backingstoremaxzoomall = 5
backingstoremaxzoombuildingsprops = 5
backingstoremaxzoomterrain = 5
backingstoremaxzoomflora = 5
shadowquality = 2
minvehiclezoom = 3
minpedzoom = 4
cursortype = 1
depthoffset = 2
debugtexture = 0
dirtyrectmergeframes = 4
sounddetail = 2
buildingvariety = 2
buildingloaderspeed = 1
modellodoffset = 0
stringtexturecachesize = 1024

particleeffectslod = 5
splattexturescale = 50
texbindmaxfree = 8
particledensity = 1
particledamping = 0
particlescale = 1
lightingupdatedelta = 0.0001
shadowmodelthreshold = 12
demolishmodelthreshold = 12
rendermodelthreshold = 6
rendermodelthresholdscroll = 40
particlesizethreshold = 300
maxvehiclepct = 1
maxpedpct = 1
opaqueuialphavalue = 0.55

 

I also tried downloading the "Graphics Rules Maker," but it is not working. The application does not see my "SimCity 4.exe" file in the App folder. Although when I go to the folder myself, the .exe file is clearly listed in the folder. I wonder why the application failed to recognize it. 

[rsc204 21,808]

37 minutes ago, Pepe The Great said:

The application does not see my "SimCity 4.exe" file in the App folder. Although when I go to the folder myself, the .exe file is clearly listed in the folder. I wonder why the application failed to recognize it.

It's not looking for the .exe, rather the directory where the game is installed, i.e. one folder back from Apps, remove that and it should work. Looking at the log, your GPU is detected but FastCard is not correctly activating. However, there is a specific setting "Force card as fast graphics card" that should fix that.

[Pepe The Great 227]

52 minutes ago, rsc204 said:

It's not looking for the .exe, rather the directory where the game is installed, i.e. one folder back from Apps, remove that and it should work. Looking at the log, your GPU is detected but FastCard is not correctly activating. However, there is a specific setting "Force card as fast graphics card" that should fix that.

Thanks for the reply. The "Graphics Rules Maker" successfully detected my game. But after I booted into the SimCity 4, I did not see any improvement with my fps. It averages somewhere between 15fps to 30fps, rarely going above 30fps, sometimes even dipping below 10fps, which was the fps I got before installing "Graphics Rules Maker." Is this normal? I am playing on a 2k monitor btw. 

[rsc204 21,808]

16 hours ago, Pepe The Great said:

But after I booted into the SimCity 4, I did not see any improvement with my fps. It averages somewhere between 15fps to 30fps, rarely going above 30fps, sometimes even dipping below 10fps, which was the fps I got before installing "Graphics Rules Maker." Is this normal?

The actual FPS for a game like SC4 is just a totally irrelevant number, this isn't a fast-paced action shooter where such things matter. Is the game itself running slow?, that's the question and it's a very hard thing to be definitive about.

On one side the game uses very old code, which whilst remaining compatible with modern systems/processes, has no optimisation which would be needed to take full advantage of them. Legacy DirectX compatibility is the number one factor in terms of performance, if this is set correctly things will run as well as they are able. But to put that into context, an ATI Radeon 3870 with 512MB RAM from 2007 can run the game every bit as well as a much newer NVidia GTX 960 with 4GB RAM. In fact, I know from my own experience that both the mobile GeForce 9800m and even an Intel HD4600 iGPU both work just as well. Caveats, there is a performance penalty because these use shared memory with the system, plus shadows never seem quite right with the Intel chip.

So the question is, do you feel like the performance is poor based purely on the FPS, or is it poor relative to SC4 more generally? So for example when I upgraded my GTX 750ti to the GTX 960, I had a ton of problems getting things working as they used too. Eventually I managed to do so, but that problem was ultimately tracked back to a motherboard utility by ASUS which was messing with SC4. Since the GPU upgrade I have also been using a 2k monitor, playing in 2k using a DXWrapper, performance is as good as I've ever seen now.

If you play vanilla SC4 without mods, it would take a very long time/high population before the game started becoming laggy and occasionally unresponsive for short periods. However the more mods you have installed, the quicker that occurs when playing, but in all likelihood this isn't the GPU itself, rather the CPU causing the problem. This is because for anything to happen on a computer, the CPU needs to process it, so when your CPU is busy, everything else may have to wait. SC4's simulation requires an exponential number of calculations that rises as the population of a city/region does. So once you hit a certain population, especially when running the traffic simulator (to find sims jobs), your will hit the limit of what your CPU can handle. It doesn't matter what CPU you have either, when I bought my i7 4770 system it was literally the fastest single-core performing CPU money could buy. But SC4 can't use more than one core without becoming hideously unstable, whereas all the advancements in CPUs since the Pentium D series (2005) have been targeted at a multi-core world. Not to mention core technologies that take advantage of newer processors, simply aren't catered for by the code of SC4, meaning you can't really fully use one core either. Single core performance is about the last thing CPU makers are considering when they make new models, we're moving from the MutilCore to ManyCore world these days. That said, due to improvements, single-core performance does get better each year, but it depends on the specific CPU you have.

Again I can give an example, having upgraded from an z87 to z97 chipset, using a newer i7 4970k coupled with faster RAM and SSD, SC4 performance didn't improve in any noticeable way. The base clocks are 3.4Ghz v.s. 4Ghz with TurboBoost to 3.9Ghz or 4.4Ghz respectively. Benchmarks show around a 10% potential increase in performance between the two chips, but the reality is even with tasks that do take my PC to it's limit, like rendering in 3DSMax/Handbrake, again no noticeable performance benefit between the two. I run both systems, but the 4970k was relegated to my test/backup machine, because in reality it runs hotter (my system can deal with it), and uses far more energy at all times, whilst giving no applicable benefit in real terms. As such I prefer to keep the 4770, which isn't even the unlocked K edition. Because, rather than chasing each Mhz of performance, I value having a reliable, cool and quiet system a lot more than overclocking so I saved myself 30€ on the CPU. But what having the 4790k (pretty much by chance) has clearly demonstrated, is that pushing your system beyond it's limits to eek out a few percent more performance is really a waste of time and money. Because the 4790k running stock represents conditions that the 4770k is simply incapable of without a ridiculous cooling system. Just because your hardware is 10% faster, does not mean your OS and Software will run 10% faster using it, there are so many other factors you have to consider.

[Pepe The Great 227]

6 hours ago, rsc204 said:

The actual FPS for a game like SC4 is just a totally irrelevant number, this isn't a fast-paced action shooter where such things matter. Is the game itself running slow?, that's the question and it's a very hard thing to be definitive about.

On one side the game uses very old code, which whilst remaining compatible with modern systems/processes, has no optimisation which would be needed to take full advantage of them. Legacy DirectX compatibility is the number one factor in terms of performance, if this is set correctly things will run as well as they are able. But to put that into context, an ATI Radeon 3870 with 512MB RAM from 2007 can run the game every bit as well as a much newer NVidia GTX 960 with 4GB RAM. In fact, I know from my own experience that both the mobile GeForce 9800m and even an Intel HD4600 iGPU both work just as well. Caveats, there is a performance penalty because these use shared memory with the system, plus shadows never seem quite right with the Intel chip.

So the question is, do you feel like the performance is poor based purely on the FPS, or is it poor relative to SC4 more generally? So for example when I upgraded my GTX 750ti to the GTX 960, I had a ton of problems getting things working as they used too. Eventually I managed to do so, but that problem was ultimately tracked back to a motherboard utility by ASUS which was messing with SC4. Since the GPU upgrade I have also been using a 2k monitor, playing in 2k using a DXWrapper, performance is as good as I've ever seen now.

If you play vanilla SC4 without mods, it would take a very long time/high population before the game started becoming laggy and occasionally unresponsive for short periods. However the more mods you have installed, the quicker that occurs when playing, but in all likelihood this isn't the GPU itself, rather the CPU causing the problem. This is because for anything to happen on a computer, the CPU needs to process it, so when your CPU is busy, everything else may have to wait. SC4's simulation requires an exponential number of calculations that rises as the population of a city/region does. So once you hit a certain population, especially when running the traffic simulator (to find sims jobs), your will hit the limit of what your CPU can handle. It doesn't matter what CPU you have either, when I bought my i7 4770 system it was literally the fastest single-core performing CPU money could buy. But SC4 can't use more than one core without becoming hideously unstable, whereas all the advancements in CPUs since the Pentium D series (2005) have been targeted at a multi-core world. Not to mention core technologies that take advantage of newer processors, simply aren't catered for by the code of SC4, meaning you can't really fully use one core either. Single core performance is about the last thing CPU makers are considering when they make new models, we're moving from the MutilCore to ManyCore world these days. That said, due to improvements, single-core performance does get better each year, but it depends on the specific CPU you have.

Again I can give an example, having upgraded from an z87 to z97 chipset, using a newer i7 4970k coupled with faster RAM and SSD, SC4 performance didn't improve in any noticeable way. The base clocks are 3.4Ghz v.s. 4Ghz with TurboBoost to 3.9Ghz or 4.4Ghz respectively. Benchmarks show around a 10% potential increase in performance between the two chips, but the reality is even with tasks that do take my PC to it's limit, like rendering in 3DSMax/Handbrake, again no noticeable performance benefit between the two. I run both systems, but the 4970k was relegated to my test/backup machine, because in reality it runs hotter (my system can deal with it), and uses far more energy at all times, whilst giving no applicable benefit in real terms. As such I prefer to keep the 4770, which isn't even the unlocked K edition. Because, rather than chasing each Mhz of performance, I value having a reliable, cool and quiet system a lot more than overclocking so I saved myself 30€ on the CPU. But what having the 4790k (pretty much by chance) has clearly demonstrated, is that pushing your system beyond it's limits to eek out a few percent more performance is really a waste of time and money. Because the 4790k running stock represents conditions that the 4770k is simply incapable of without a ridiculous cooling system. Just because your hardware is 10% faster, does not mean your OS and Software will run 10% faster using it, there are so many other factors you have to consider.

Thank you for the detailed explanation. I guess the only thing that will solve this problem is having a SimCity 4 remaster. 

[Pepe The Great 227]

On 1/30/2023 at 4:13 AM, rsc204 said:

The actual FPS for a game like SC4 is just a totally irrelevant number, this isn't a fast-paced action shooter where such things matter. Is the game itself running slow?, that's the question and it's a very hard thing to be definitive about.

On one side the game uses very old code, which whilst remaining compatible with modern systems/processes, has no optimisation which would be needed to take full advantage of them. Legacy DirectX compatibility is the number one factor in terms of performance, if this is set correctly things will run as well as they are able. But to put that into context, an ATI Radeon 3870 with 512MB RAM from 2007 can run the game every bit as well as a much newer NVidia GTX 960 with 4GB RAM. In fact, I know from my own experience that both the mobile GeForce 9800m and even an Intel HD4600 iGPU both work just as well. Caveats, there is a performance penalty because these use shared memory with the system, plus shadows never seem quite right with the Intel chip.

So the question is, do you feel like the performance is poor based purely on the FPS, or is it poor relative to SC4 more generally? So for example when I upgraded my GTX 750ti to the GTX 960, I had a ton of problems getting things working as they used too. Eventually I managed to do so, but that problem was ultimately tracked back to a motherboard utility by ASUS which was messing with SC4. Since the GPU upgrade I have also been using a 2k monitor, playing in 2k using a DXWrapper, performance is as good as I've ever seen now.

If you play vanilla SC4 without mods, it would take a very long time/high population before the game started becoming laggy and occasionally unresponsive for short periods. However the more mods you have installed, the quicker that occurs when playing, but in all likelihood this isn't the GPU itself, rather the CPU causing the problem. This is because for anything to happen on a computer, the CPU needs to process it, so when your CPU is busy, everything else may have to wait. SC4's simulation requires an exponential number of calculations that rises as the population of a city/region does. So once you hit a certain population, especially when running the traffic simulator (to find sims jobs), your will hit the limit of what your CPU can handle. It doesn't matter what CPU you have either, when I bought my i7 4770 system it was literally the fastest single-core performing CPU money could buy. But SC4 can't use more than one core without becoming hideously unstable, whereas all the advancements in CPUs since the Pentium D series (2005) have been targeted at a multi-core world. Not to mention core technologies that take advantage of newer processors, simply aren't catered for by the code of SC4, meaning you can't really fully use one core either. Single core performance is about the last thing CPU makers are considering when they make new models, we're moving from the MutilCore to ManyCore world these days. That said, due to improvements, single-core performance does get better each year, but it depends on the specific CPU you have.

Again I can give an example, having upgraded from an z87 to z97 chipset, using a newer i7 4970k coupled with faster RAM and SSD, SC4 performance didn't improve in any noticeable way. The base clocks are 3.4Ghz v.s. 4Ghz with TurboBoost to 3.9Ghz or 4.4Ghz respectively. Benchmarks show around a 10% potential increase in performance between the two chips, but the reality is even with tasks that do take my PC to it's limit, like rendering in 3DSMax/Handbrake, again no noticeable performance benefit between the two. I run both systems, but the 4970k was relegated to my test/backup machine, because in reality it runs hotter (my system can deal with it), and uses far more energy at all times, whilst giving no applicable benefit in real terms. As such I prefer to keep the 4770, which isn't even the unlocked K edition. Because, rather than chasing each Mhz of performance, I value having a reliable, cool and quiet system a lot more than overclocking so I saved myself 30€ on the CPU. But what having the 4790k (pretty much by chance) has clearly demonstrated, is that pushing your system beyond it's limits to eek out a few percent more performance is really a waste of time and money. Because the 4790k running stock represents conditions that the 4770k is simply incapable of without a ridiculous cooling system. Just because your hardware is 10% faster, does not mean your OS and Software will run 10% faster using it, there are so many other factors you have to consider.

Hello rsc204, yesterday I switch from dxwrpper to dgvoodoo. dgvoodoo allows me to obtain higher fps, which makes the gameplay smoother, I can achieve above 30fps now, which makes moving around the map and building things a lot easier. Before I was stuck at below 15fps and often times the game ran on single-digit fps, and the whole gameplay experience was horrible. However, I also notice that after installing dgvoodoo, my fps is also very unstable. Sometimes, the game will dip to 1 fps, and have minor freezes, but the game returns to normal after a few seconds. I don't know what is causing this lagging issue and hope you may shine some light on it. My biggest question now is how to set the directory for dgvoodoo, currently, it is set at D:/Steam/Steamapps/Common/SimCity 4 Deluxe/App. Thanks!

[rsc204 21,808]

Well I think that shows that dgVoodoo2 is simply doing a better job of backwards compatibility with SC4.

The FPS being unstable is simply a factor of how the game works.

How often is the dip happening?, if it's only every now and again them most likely the Traffic Simulator is running and everything else is waiting to catch up. If you've a small population you don't notice it, but it always happens eventually and as the population continues to grow, as it does it takes longer to clear, this is quite normal. But if this is happening with a new/empty city/region, then it suggests there is still a problem that needs solving.

Once more though what is more important that any FPS figure, is whether or not the game feels responsive. That things have suddenly improved with the switch to dgVoodoo2 suggests to me you've resolved the main problem.

As for the directory for dgVoodoo2, I'm sure you've got it correct, otherwise the effects of that Wrapper would not be apparent. This app includes a handy feature, under the DirectX tab check the box "dgVoodoo Watermark", then when you run SC4 you will see the dgVoodoo logo overlaid, which shows you it is running. Although you probably only want to run with it on once to check, since it's annoying normally.

[Pepe The Great 227]

1 hour ago, rsc204 said:

Well I think that shows that dgVoodoo2 is simply doing a better job of backwards compatibility with SC4.

The FPS being unstable is simply a factor of how the game works.

How often is the dip happening?, if it's only every now and again them most likely the Traffic Simulator is running and everything else is waiting to catch up. If you've a small population you don't notice it, but it always happens eventually and as the population continues to grow, as it does it takes longer to clear, this is quite normal. But if this is happening with a new/empty city/region, then it suggests there is still a problem that needs solving.

Once more though what is more important that any FPS figure, is whether or not the game feels responsive. That things have suddenly improved with the switch to dgVoodoo2 suggests to me you've resolved the main problem.

As for the directory for dgVoodoo2, I'm sure you've got it correct, otherwise the effects of that Wrapper would not be apparent. This app includes a handy feature, under the DirectX tab check the box "dgVoodoo Watermark", then when you run SC4 you will see the dgVoodoo logo overlaid, which shows you it is running. Although you probably only want to run with it on once to check, since it's annoying normally.

Thanks for the reply. You made a good point regarding the "traffic simulator." My fps is very stable when I am on the regional map, where car and pedestrian traffic are not simulated. However, when I load my current map, which is a large city on a large map approaching 60k population, it has constant stuttering. I believe it could be caused by the number of cars/vehicles that are being simulated on the map. If there is a way to lower the amount of car simulation, maybe my fps would be more stable. I think the current amount of cars being simulated on the map is unrealistic for a city with merely 60k population. I do have a PCIe SSD on my computer, which is faster than a normal SSD. Do you think the stuttering issue will be mitigated if I move the game onto the PCIe drive? 

[Ulisse Wolf 4,412]

44 minutes ago, Pepe The Great said:

Thanks for the reply. You made a good point regarding the "traffic simulator." My fps is very stable when I am on the regional map, where car and pedestrian traffic are not simulated. However, when I load my current map, which is a large city on a large map approaching 60k population, it has constant stuttering. I believe it could be caused by the number of cars/vehicles that are being simulated on the map. If there is a way to lower the amount of car simulation, maybe my fps would be more stable. I think the current amount of cars being simulated on the map is unrealistic for a city with merely 60k population. I do have a PCIe SSD on my computer, which is faster than a normal SSD. Do you think the stuttering issue will be mitigated if I move the game onto the PCIe drive? 

SC4 should always be installed on an SSD (Better NVMe SSD) as it is a very intensive application

[rsc204 21,808]

12 hours ago, Pepe The Great said:

I do have a PCIe SSD on my computer, which is faster than a normal SSD.

So do I, in theory it's over 3x faster at reading data, in practise it makes no difference with SC4. Again, the architecture of the game was built at a time when SSDs were a pipe dream and the game hits a limit somewhere between regular HDD and SDD speeds in terms of throughput. Tests have been carried out too with RAMDisks, which should be even faster, it just doesn't result in improved performance in SC4.

Constant juddering is not good, but is unlikely to be down to the number of cars you are seeing, again SC4 can't use a fraction of the power of your GPU, there is no lag there. Are you using the Radical automata mod as part of the NAM?, either way the NAM installer offers a number of choices that control how many cars you see. I'd test some of the options to see if it helps, but I'm not entirely convinced it will make a difference.