Is anyone NOT experiencing video stutters? Performance..

[wyskass]

I'm curious if there are people who don't experience any video stutters, running Simrail.. If so please what kind of system and configuration are you using?

I get quite bothered by random video jerks and stutters and have done EVERYTHING I can think of to identify, quantify, correlate and try to eliminate. To be fair this isn't the only game, but it doesn't happen in every game, or at least it's less noticable in others. 

I have a Ryzen 9800X3D, with 7900XT GPU, 64GB low latency DRAM, and a NVME ssd. So it's a pretty good system. I'm running medium-high settings, with minimized LOD, 1/2 textures, and relatively high draw distances. I get from 40 to 120 FPS depending on area. Simrail is definitely CPU limited, and mostly single thread, as many games are. I gathered extensive PC metrics of Frametime generation data, as well as VRAM, CPU and GPU activities, and made graphs and used python scripting to compare all different settings. I can most definitely correlate every stutter to exactly the times when content is being moved into VRAM, so there is some I/O wait. I've optimized my VRAM timings and tuned and optimized CPU per core. I've played with different graphics settings in Simrail, and checked all background activities and driver latencies.. There is literally nothing that makes a change in this and is independent of FPS. I assume it's the game architecture and Unity, and just can't be helped, unless devs optimize better.

Is this happening to everyone? Do people just learn to deal with this?

Mike

Edited Sunday at 05:20 AM by wyskass

[Sean the Sheep]

Out of interest, does your framerate AND your graphics card usage go down around Warsaw? Is that how you diagnosed the single thread issue?

 

[wyskass]

3 hours ago, Sean the Sheep said:

Out of interest, does your framerate AND your graphics card usage go down around Warsaw? Is that how you diagnosed the single thread issue?

tl;dr:  Yes, for sure. And that's expected, considering Warsaw has a very high number of objects and complex scenery to render. So yes, in these areas the CPU is maxed out processing the high number of objects to feed to GPU and the GPU is waiting (lower usage), slowing the frame generation time. To determine actual CPU bottleneck, you have to look at just the CPU Core executing simrail.exe. It's only that single thread that is consistently running at a certain ceiling, and other assisting threads often wait for that one. Like most DX11 games, though this is not surprising though.

 

Hope you like geeking out on PC performance analytics.. 🙂 ->

This is a benchmark I ran many times. It's a Pendolino run from Warszawa Wschodnia and ending at bridge just past Ursus Niedzwiadek.

Location references: The vertical purple lines are stop and start marks (programmed hotkey on mouse to log event, while driving): 1. Starting at Wschodnia 2. A scenario stop signal just before tunnel into Centralna 3. Stop at Centralna, waiting 3 minutes 4. Leaving Centralna, 5 Stop Zachodnia, wait, 6 Leave Zachodnia. Then high speed through the suburbs toward Piastow.

Median Framrates: As you can see Framerate (black dotted) FPS is up above 110 on the west side of city, then at its lowest waiting at Zachodnia, down to 50 FPS. NOTE that this is median FPS, and it's not a problem.

CPU/GPU load: Purple and green lines shows Max Thread/CPU % and GPU Util %. This basically represents the simrail.exe main single thread on one CPU never reaching 100% because of I/O and Freq max limits. And GPU % Util, which expectedly correlates to framerate. If the GPU isn't working at max capacity, it's waiting for the CPU to send it content. Note that the 3 minutes waiting at Zachodnia, a complex environment, it only works at 80% and is lowest FPS. CPU can't process the world fast enough to feed it. I also delved deeper tracking median and mean Effective Frequency of CPU relative to its Max boost freq, looking at it's % of potential capacity and I/O waiting.

Micro Stutter: Short yellow lines are stutter events, defined as indivdual or a few frames which are significantly slower than that running avg over 1 second.  This of course also visible by the key metric of blue line which are frametimes (1 second avg).. Not the very regular toothed pattern, of I/O blockage in the graphics pipeline. Many of these are actually not perceived because they aren't intense, and is one of 2 stutter patterns. The game, graphics API runs some kind of cyclical around every 20 second process ending with a blockage.

PROBLEM: Heavy stutter: The full vertical yellow lines are timestamps, where I experienced a noticable stutter in the video, and marked it while driving. Red lines mark major stutter event, a few stutters in a row. Notice the VRAM use profile line (green) in the middle. EVERY time there is a change (load/unload) of scenery content for the GPU, there is a noticable stutter. There is a major break in the I/O process for a few different possible reasons. Fractions of seconds but usually a few in a row, enough to be psychologically unpleasant especially when we're so focused on perceiving velocity as train drivers. 

The biggest stutter is nearing the tunnel to Centralna from the west, and then entering the Zachodnia station area, which is illustrated by the VRAM activity. 

MEDIAN FRAMERATE IS UNRELATED TO THE STUTTER PROBLEM - No amount of computing power fixes this.

So, in all the testing and comparing CPU, GPU settings, tunings, overclocking and game graphics settings, the Stutters NEVER really change. In fact, I even replaced my 7800X Ryzen and 7800XT Radeon, with the 98000X3D and 7900XT, hoping maybe the extra L3 cache would buffer these stalls.. Nope. I definitely increased my FPS, but not the 2nd type of stutter.  

To be fair.. DX11 is thread limited AND Simrail is procedurally generated content for hundreds of kilometers or real world scenery, which cannot be optimized asset by asset as many games are. It allows game developers to create big worlds and lots of vehicle models and operational logic and all the fun game stuff.. when they don't have to manage graphics details, which can be layered on top of Unity and abstracted. But at a cost of performance and CPU inefficiency. 

BUT STILL I ASK.. Does anyone have stutter free experiences in Simrail? I'm very curious.

Edited Sunday at 05:39 PM by wyskass

[Shiralyn]

Operating System: Kubuntu 25.10
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2
Kernel Version: 6.17.0-6-generic (64-bit)
Graphics Platform: X11
Processors: 16 × Intel® Core™ i9-10885H CPU @ 2.40GHz
Memory: 64 GiB of RAM (62,5 GiB usable)
Graphics Processor: Quadro RTX 5000 with Max-Q Design
Manufacturer: Dell Inc.
Product Name: Precision 7550

I only stutter when tabbing in / out but that happens for all games. Upscaling might be what is saving me.

settings.txt

[wyskass]

10 hours ago, Shiralyn said:

Operating System: Kubuntu 25.10
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2
Kernel Version: 6.17.0-6-generic (64-bit)
Graphics Platform: X11
Processors: 16 × Intel® Core™ i9-10885H CPU @ 2.40GHz
Memory: 64 GiB of RAM (62,5 GiB usable)
Graphics Processor: Quadro RTX 5000 with Max-Q Design
Manufacturer: Dell Inc.
Product Name: Precision 7550

I only stutter when tabbing in / out but that happens for all games. Upscaling might be what is saving me.

settings.txt 5.03 kB · 2 downloads

Thanks for sharing. I wonder if some of these settings aren't revealed through the game UI.

[Shiralyn]

14 hours ago, wyskass said:

Thanks for sharing. I wonder if some of these settings aren't revealed through the game UI.

These are mostly ingame but it contains some game settings not ingame, some not shown in game for upcoming features or professional sim features not working in game but I believe all graphics settings can be found in game. I should also mention that I get much worse performance on long ride, yesterday I did Krakow - Warsaw and got real bad lag but not really stutters close to Grodzisk, my mouse starts getting like delayed input but that might be a linux user problem.

Edited Tuesday at 10:56 AM by Shiralyn