What's with this games VRAM usage?

[Yamete Kudasai]

TL;DR: Why does the game use 6+ GB of VRAM and why is the game running badly even though no part of my system is maxed out?

I have no mods or assets enabled, no map themes, no color corrections nothing. The game uses about 4.3GB of RAM (which is totally fine) but also about 6GB of VRAM. Neither CPU nor GPU usage are maxed out, RAM and VRAM aren't maxed out either.

'bigger' cities with several tens of thousands citiziens push my framerate down to 40ish with CPU and GPU usage well below 80%.

I'm not complaining about simulation games taking good hardware to run well but I'm wondering where the bottleneck is because I can't see an obvious one.

Running the game at 3440x1440 on an i7-8700K, GTX 1080 and 16GB 3200Mhz CL16 RAM

[Finwickle]

Check your CPU and look at load per core. One of the simulation processes might be hitting one core to 80+% and be your bottleneck.
40 fps is quite decent for this game btw. And anything above 30 fps should be fine for the type of game.

[Yamete Kudasai]

Originally posted by Finwickle:

Check your CPU and look at load per core. One of the simulation processes might be hitting one core to 80+% and be your bottleneck.
40 fps is quite decent for this game btw. And anything above 30 fps should be fine for the type of game.

Most cores sit at 50ish percent, some at 20ish percent. The highest I've seen is ~70% usage. Haven't seen any core spike to 100% yet.

[Finwickle]

Hmm, can't help you then. I know the game isn't well optimized and is known to get to a low fps even on good hardware. It should logically show on hardware statistics, but there are many more posts on the forum about the same issue. CPU usage could be very spikey with maybe disk requests in between, or wait time for other processes or GPU, which would explain the 50% average on core usage. But it's all just guess work here.

[Yamete Kudasai]

Yeah. I'd love to know how this game manages to fill up 6-8 GBs of VRAM though.
Sure, I'm running at 3440x1440 but VRAM usage still shouldn't be THAT high in a game like this.

[Finwickle]

It might just use whatever VRAM it can get its hands on to get all graphic stuff done :-)

[Yamete Kudasai]

Originally posted by Finwickle:

It might just use whatever VRAM it can get its hands on to get all graphic stuff done :-)

Yeah but you need to fill that VRAM with data, more specifically pixel and vertex data. Most modern games only manage to fill up 8GB of VRAM on high resolution when using high poly meshes and high resolution textures.

[CyberVibes]

The game loads all assets into the pagefile on load of a game then when you use an asset it gets swapped to the physical memory, so what your seeing there is quite normal.

[Yamete Kudasai]

Originally posted by CyberVibes:

The game loads all assets into the pagefile on load of a game then when you use an asset it gets swapped to the physical memory, so what your seeing there is quite normal.

Wouldn't that mean though that in the beginning of a game my dedicated VRAM usage should be quite low? Especially with no custom assets enabled?
I'm intrigued.

[MarkJohnson]

The game seems to load everything into RAM on launch. So it fills up vram. Mine loads at 5.9GB iirc. Vega64. I don't use workshop. It's all vanilla. At boot, my system is at 7.7GB RAM, Game loaded it is at 13.4GB. Pagefile boots to 10.6 GB and sits at 23.0 GB with game loaded.

GPU vRAM is 63% or 6.9GB

Cities.exe is 5.664 GB.

I get around 30-40 fps zoomed-in all of the way on my new Dell gaming monitor. Some areas are over 50fps in the more empty areas. I was only getting around 27-32 fps before. Not sure why it went up from a monitor?

[Yamete Kudasai]

Originally posted by -DI- rmjohnson144:

I get around 30-40 fps zoomed-in all of the way on my new Dell gaming monitor. Some areas are over 50fps in the more empty areas. I was only getting around 27-32 fps before. Not sure why it went up from a monitor?

Weird, you didn't move down in resolution did you?

[MarkJohnson]

Yes, I went from 4k to 1440p. But I've lowered my resolution before to 1080p and even connected my 1080p monitor with no changes.

I do see lower monitor ms scores improve by 50% or more. Maybe that is helping? Maybe a smaller city. I usually test on larger cities. But I've seen others with same rig as me and 1080p monitors and same low scores as I get.

Maybe it is Dell. I bought a Dell this time as it was cheaper cheaper this time, because of the p;rice hikes last year from those data miners. Then I had over $100 reward points from Dell, so I got this Dell monitor it was cheapest I could find, plus 10% extra discount from sale code. The monitor has a driver with it as well.

Maybe I'll be thankful and not look a gift horse in the mouth. lol

[Yamete Kudasai]

Originally posted by -DI- rmjohnson144:

Yes, I went from 4k to 1440p. But I've lowered my resolution before to 1080p and even connected my 1080p monitor with no changes.

I do see lower monitor ms scores improve by 50% or more. Maybe that is helping? Maybe a smaller city. I usually test on larger cities. But I've seen others with same rig as me and 1080p monitors and same low scores as I get.

Maybe it is Dell. I bought a Dell this time as it was cheaper cheaper this time, because of the p;rice hikes last year from those data miners. Then I had over $100 reward points from Dell, so I got this Dell monitor it was cheapest I could find, plus 10% extra discount from sale code. The monitor has a driver with it as well.

Maybe I'll be thankful and not look a gift horse in the mouth. lol

The monitor itself shouldn't affect fps though. Maybe Vsync did weird things before or something.

In my case it's the VRAM that's bottlenecking me, lowering graphics settings or moving down in resolution only increases FPS by maybe 5% or so.

Using the dynamicresolution mod going from 150% to 50% scaling doesn't affect FPS in any significant way while decreasing visual quality drastically. (Again, playing at 3440x1440)

[MarkJohnson]

Why do you think vram is bottlenecking you? vram is just plain old ram. i.e. memory, like ssd/hdd/usb flash drive, cd, etc. Just faster.

[Yamete Kudasai]

Originally posted by -DI- rmjohnson144:

Why do you think vram is bottlenecking you? vram is just plain old ram. i.e. memory, like ssd/hdd/usb flash drive, cd, etc. Just faster.

Let's say the game uses 10GB of VRAM but your GPU has only 8GB. The game is now going to store 2GB of data in a page-/swapfile on your HDD/SSD. Whenever the game needs data from those 2GB on the HDD/SSD it swaps out some data in the VRAM (hence the name swapfile) with the data it needs, which is really slow in computer terms.

Which means if a program needs more RAM / VRAM than you have performance is going to suffer, a lot.


How do I tell my VRAM is bottlenecking me? CPU and GPU usage are well below 60% most of the time, my RAM isn't filled up my VRAM however is beyond full.

[MarkJohnson]

Originally posted by Exidrial:

Originally posted by -DI- rmjohnson144:

Why do you think vram is bottlenecking you? vram is just plain old ram. i.e. memory, like ssd/hdd/usb flash drive, cd, etc. Just faster.

Let's say the game uses 10GB of VRAM but your GPU has only 8GB. The game is now going to store 2GB of data in a page-/swapfile on your HDD/SSD. Whenever the game needs data from those 2GB on the HDD/SSD it swaps out some data in the VRAM (hence the name swapfile) with the data it needs, which is really slow in computer terms.

Which means if a program needs more RAM / VRAM than you have performance is going to suffer, a lot.


How do I tell my VRAM is bottlenecking me? CPU and GPU usage are well below 60% most of the time, my RAM isn't filled up my VRAM however is beyond full.

But the stuff being loaded in vram isn't even being used. It is just waiting to be used. So it pages it out as it sees fit.

Unless you have plopped several hundreds of workshop in your game. you are fine. But you already said your vram isn't maxed out. So this can't be the issue. Otherwise your vram would be maxed at 100% at all times, and your disk activity would be running constantly.

This game simply has has low fps, because it's a simulation and it is designed to save resources by not needlessly drawing constant pictures, when it needs to run the AI for simulation. Not to mention the Unity game engine interferes with the FPS as it has a lot of overhead.

Your system is running as good as it gets. Minus workshop issues. Remove workshop )i.e. mods) and your city will resume normally.

Wjat is your GPU activity? It is shown in task manager. It will have GPU usage, vram usage, vram pagefile. Check you disk activity as well.