For those who TLDR - it's CPUs only 1 core usage by game engine issue.
Since we spammed all over 1.39 beta thread and since I found an opportunity to fully test ATS performance on my mid PC and another high end PC all together, I did so. My desire was to finally find a 100% answer to why game stutters or lags in special locations, when you go to lobby/map/any other menu and come back, or any other instance. Question that was asked is that a pc hardware bottleneck or is it a game engine problem. Here are my findings.
Test zone:
Mid PC Specs:
Intel i5 6600 3.3GHz (4 cores)
16GB RAM DDR4
Nvidia GTX1080 8GB DDR5
Game installed on 500gb SSD Sata disk with Raid0 (windows uses 2 exact SSDs to act as one disk , but x2 faster)
1080p Monitor
High End PC Specs:
Intel i7 9700K 3.6GHz (overclocked to 4.7GHz and 8 cores)
16GB RAM DDR4
Nvidia RTX2060 super 8GB DDR6
Game installed on 1tb SSD m2
4K Monitor
Performance data was taken live from standard windows task manager running on second monitor
All the tests where done on 1.38 version of ATS with all map DLCs included
Game settings where all on High/Ultra as possible, everything maxed up, except:
- vsync off all the time
- scaling 400%+1080p resolution on mid pc at all tests
- scaling 200%+4K resolution on high end pc at all tests
2 game frames where tested - totally vanilla game and game with solid non-maps mod pack that is actually game I normally play.
Mod list:
- All Jazzycat traffic mods , except mexican
- All Jazzycat trailers and cargo mods
- Realistic graphics mod
- Real companies 2.0
- Sound fixes pack
- Local municipal police traffic pack
- SISL Radio
- SISL flat UI
- John Rudas' Freighliner classic XL + Trailers pack (including its wheel and flares packs)
- ATS real logos project
- Real advertisments
[ external image ]
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Results:
Findings are not something extraordinary and were actually expected.
At heaviest location, with mods on mid PC game almost doesn't use SSD load. It stood on around 1% at all tests. (Its important, because stuttering in gaming is normally HDD/SSD speed bottleneck issue)
RAM usage never exceeded 8GB.
GPU load was around 80-100% on both PCs and affected mostly fps as expected and not stutters. Fun fact - when I dropped High End PC from 4k to 1080p and 200% scale, GPU load dropped to 50% and FPS gain was about...10...In Twin Falls. Well done SCS.
CPU Load was the most important factor that affected entire game on BOTH PCs. First of all I found out that only 1st and last core of CPU were active while testing. And while 1st core load was about 80-90+% all the time, last core ran at about 20% (probably windows used it for its background operations I think).
ALL THE CPU LOAD % ARE ACCORDED TO 1st CORE LOAD ONLY, SINCE GAME JUST DIDN'T USE OTHER CORES
Mid PC Vanilla game - no stutters on map/menu jumps, no stutters at random locations, no stutters but 10-20 fps drop in Boise, sudden heavy stutters in Twin Falls from cemetery to farm locations at west and 10-20 fps drop. Fps drop was in almost entire city. CPU Load about 80-90% normally, 95% at fps drops locations and stable 100% on heavy stutters locations.
Mid PC Mods active default truck - same as previous, except slight stutters at Boise. CPU load went up to 90% normally, 95-100% at fps drop locations and heavy 100% stable load in Twin Falls.
Mid PC Mods active + Freightliner mod truck - heavy stutters on map/menu jumps, slight stutters at random locations, stutters in Boise and HEAVY stutters in Twin falls. CPU load was about 95% normally, 95-100% at random locations and Boise, 100% at Twin Falls.
High End PC Vanilla game - no stutters at any locations. CPU load around 70-80% normally, 85% at Boise and 90% at Twin Falls
High End PC Mods active default truck - no stutters on map/menu jumps, no stutters at random locations , no stutters at Boise, slight stutters in Twin Falls. CPU load around 80-85% normally, 90-95% Boise, 95-100% Twin Falls.
High End PC Mods active + Freightliner mod truck - no stutters on map/menu jump, no stutters at random locations, slight stutter at Boise, HEAVY stutters in Twin Falls. CPU load around 90% normally, 95-100% Boise, 100% stable heavy load in Twin Falls.
***Interesting fact - after BIOS update to latest 2020 version on High End PC, CPU load in game with mods and truck mod reduced to 3-5% and so stutters stopped to appear at any locations in game. BIOS update on mid PC didn't affect game performance at all.
Conclusion:
Entire game stuttering problem occurs because of game engine using only one core of any CPU and so game bottlenecks itself to a single core CPU performance. As better your CPU operates at single core (high GHz rate is important), so less stutters will occur in your game. Game stuttering problem became noticeable now, because to withstand novadays map design standards developers pushed game engine to its ceiling and so even on high end pcs, game uses almost all single core resources at heavy locations. Mods overload the core even more. It doesn't really matter which one, I removed mods one by one and tested performance, it more about quantity of the mods. As more you have, more they use CPU core's resources. Except Truck mods, which use much more resources than any other mod I tested.
Stuttering on map/menu jumps or long map loads problem that appeared to me is because game unloads entire game while it goes to map/menu and so on backwards. Imagine your poor 1st core struggle at 90-100% normally and than all of a sudden it should unload itself to 0 and then reload map/menu and so on backwards to game. That what make game stutter in such situations.
Ways to fix stuttering in ATS:
1. Switch to the most powerful single core performing CPU you can
2. Use less mods
3. Suffer and wait till developers wake up
In my opinion, if nothing done we will face more and more performance issues in an upcoming maps DLCs or map design advancement stop at some point.
