FPS stuttering, low GPU and CPU utilization

[ibziFox]

The stuttering is real,
I can zoom in very close and watch some traffic stutter too. Regardless of distance, it just stutters every 4 seconds or so. The stuttering just started after at around 17,000 people. What's also strange is my lower GPU and CPU usage. CPU is hovering around 46-50%, while the GPU is bouncing from low 40% to only 58%. Why not fully used?

Other notes on fps. Playing with Nvidia recommended and skylines post tweaks. Low-Medium settings overall. FPS ranges from 34-48. Zoomed in very close I can push a little over 60fps.

Quick spec:
AMD Ryzen 9 5900X
32 GB ram
GIGABYTE RTX 4090 GAMING OC
Game installed on a 1TB Samsung m.2

anyone else having issues?

[zaku49]

https://www.dsogaming.com/pc-performance-analyses/cities-skylines-2-developers-target-30fps-and-not-60fps-even-on-pc/

[Jack Fat Belly Johnsohn]

Yep i got the samme problem

[barrygreybeard]

my cpu is around 40% load and my RTX 4090 around 80%+ at around 70C... playing 2K which is quite acceptable

[ZooBeasts]

Same here, 85% GPU utilization at start, load the game, 30s later, GPU utilization suddenly drop 0% or 20%, screen freeze 2-5s,
5800x + 3090 + 48GB ram,

[Red Beard]

Originally posted by zaku49:

https://www.dsogaming.com/pc-performance-analyses/cities-skylines-2-developers-target-30fps-and-not-60fps-even-on-pc/

That has absolutely nothing to do with stuttering...

[BABarracus]

i get bad stuttering when the harddrive utilization is at 100% otherwise the game runs fine

[Los.Injurus.Bob.Blunderton]

You're choked with draw calls!
That is all there is to it. There is nothing you can do about it sadly.
I could fix this for the developers, but I'd be doing that for a paycheck, and it'd probably take several weeks.
Also, this can be fixed with multi-threaded rendering pipelines, but that's dubious at best with Unity unless they have some pre-packaged solution I haven't heard of yet (possible, being I certainly don't know everything).
STUTTERING comes from something else, like path-finding rebuild/re-work or other AI routines that run periodically. This has been inherent to city builders (the AI stutters) for the last 20 years. Don't expect that to go away anytime soon unless they distribute the load off of the rendering engine core.

[KasparL]

mine is 100% GPU but really low CPU (around 20-30%)
5800X, RTX3080 + 32GB ram
1080p, fps with custom settings (mainly turning cloud, fog, DoF off) range from 40-85 (its all over the place...depends on the camera)

[Jim Zero]

Yeah. It's not good. But I lowered my settings a bit now it's playable for me. Should hold me over till they fix it.

[AgeOfBacon]

And you know the fun thing? The game is still using more than 95% of my GPU... on the title screen. And not only on the title screen, but also in the background, when the game isn't even on screen.
There's a huge issue with this game, and it has nothing to do with graphics. They either f*cked up the entire game, or did it on purpose for some weird reason.
In any case, they won't fix it, there's no hope for it. And the fact that they admitted themselves that they're aiming for 30 FPS and not 60 means they absolutely know the game is badly made, and they're not planning to fix it.

[was_fired]

From what I can tell they did a solid job distributing compute across all of my CPUs and it hasn't pegged any of them. Given the fact that most of the game is built around running a bunch of optimized A* algorithms, rendering driving, checking preferences of independent entities, and verifying network layouts (be it power grids, water grids, or road grids) I'm honestly impressed with how well they've done at spreading it out.

Optimizing for refresh rate to the GPU feels like a largely separate issue from all of these items since in theory you can flash the screen as many times as you want without fully updating the background game state, but that's not the problem they focused on.

I don't know how hard the render refresh interval problem, but I can understand why it wasn't their focus. Unfortunately it's a metric a lot of people care about so it probably does make sense for them to try to address it.

The biggest question for how hard / easy that is comes down to how deeply integrate their massively parallel hard compute problems are with updating the picture, and only they know that.

[[BRTD]Luewen]

Originally posted by ibziBirb:

The stuttering is real,
I can zoom in very close and watch some traffic stutter too. Regardless of distance, it just stutters every 4 seconds or so. The stuttering just started after at around 17,000 people. What's also strange is my lower GPU and CPU usage. CPU is hovering around 46-50%, while the GPU is bouncing from low 40% to only 58%. Why not fully used?

Other notes on fps. Playing with Nvidia recommended and skylines post tweaks. Low-Medium settings overall. FPS ranges from 34-48. Zoomed in very close I can push a little over 60fps.

Quick spec:
AMD Ryzen 9 5900X
32 GB ram
GIGABYTE RTX 4090 GAMING OC
Game installed on a 1TB Samsung m.2

anyone else having issues?

Game i not using all cores as efficiently. Few cores take most of the load and rest are doing background tasks so in that sense those 100% working cores are bottlenecking GPU.

[Apples]

Originally posted by zaku49:

https://www.dsogaming.com/pc-performance-analyses/cities-skylines-2-developers-target-30fps-and-not-60fps-even-on-pc/

Nothing wrong with 30FPS, you don't move that fast, you don't flick in a split second as though you are shooting someone... what is it you don't get? Movies run at less, do you complain that your movie frames are not fast enough?

[[BRTD]Luewen]

Originally posted by AgeOfBacon:

And you know the fun thing? The game is still using more than 95% of my GPU... on the title screen. And not only on the title screen, but also in the background, when the game isn't even on screen.
There's a huge issue with this game, and it has nothing to do with graphics. They either f*cked up the entire game, or did it on purpose for some weird reason.
In any case, they won't fix it, there's no hope for it. And the fact that they admitted themselves that they're aiming for 30 FPS and not 60 means they absolutely know the game is badly made, and they're not planning to fix it.

Its precaching at the background when you start the game. When its done the gpu usage goes down. Make sure you also have enabled max background fps in nvidia control panel so it wont run at 100% steam when on back ground. That if you have nvidia card.

[banzaimonkey]

Originally posted by ibziBirb:

The stuttering is real,
CPU is hovering around 46-50%, while the GPU is bouncing from low 40% to only 58%. Why not fully used?

GPU will max out below 100% if you have vsync turned on.

I've read elsewhere that the engine can only handle four worker threads, which could mean that the simulation is using 100% of its CPU. You can try changing the CPU bias in General -> Performance Preference to see if this helps.

My guess would be you are RAM limited (using virtual memory or swap, which pages to disk), or there is interference from another program (virus scanner? crypto malware?).

Could be a bug but I have not experienced stuttering and my specs are well below yours.