Rust using CPU instead of GPU ?


I have low FPS while I’m playing Rust with graphics card AMD HD 6870 on Windows 8.1. Old Rust legacy just ran fine, but for some reason I think that this new Rust thinks my CPU is my GPU (?), as the activity level on my graphics card shown by Catalyst Control Center is low, while my CPU % is really high. I can’t ALT TAB without it taking ages, when I’m on desktop while Rust is running in the background everything just seems 10 times slower.

This didn’t occur on legacy, running on the maximum quality setting. Everything was fast and fluid, going to desktop while Rust is running wasn’t laggy.

I have a feeling this new Rust puts more work to the CPU, however I don’t see anyone complain about it. When I was searching on the internet for this issue, there seemed to be only 1 guy with the exact same problem/idea as me:

GPU: AMD HD 6870
CPU: Intel® Core™ i5-2320 CPU @ 3.00 GHz
OS: Windows 8.1 64 bit

More sources/solutions:

There;s been loads of posts about issues with AMD cards, its likely an issue related to that.

Same problem here. HD 6670, i5-2500K 3.3GHz
New Rust runs like shit for me.

Few updates before i didn’t have any CPU problems with Rust.
Currently it’s using mostly only CPU as op said instead GPU and i do not have amd card.
Because of that i’m not able to play on maximum settings with 60 fps (i could do that not so long ago, now i get about 20 fps)

I’m using:

Windows 7 64 bit
Intel i5-2300
Geforce GTX 660 Ti
8 GB ram

Make sure you enable PVT, in your graphics settings. It gives a good boost to your fps. I’m really not sure why it’s disabled by default honestly.

This isn’t true for everyone. I lose frames when turning PVT on, but others gain. Test it out either way and see what happens.

Also I doubt thats gonna fix the major issues people have been getting, its just gonna slightly improve some peoples experience who can already run the game decently.

The game is running at a low resolution for me since the update. Console and text are larger than normal (new UI aside). Unusually high CPU usage too.

PVT takes my ~60 fps down to ~30 fps with very bad stutter as you look around.

Still getting freezes every few seconds when walking around, even with PVT off. Solo player on a fresh server, no builds. It seems to coincide with trees or rocks being drawn in the distance. 0fps for ~1 second.

Windows 7 64-bit
i5-2400 3.1 GHz
GeForce GTX 760

GTX 660ti
i5 3770k
8gb ram
2 tb hdd

and i get a perfect 120 fps, not sure why some people get bad frames

I can confirm that I get high CPU loads aswell. I get major hiccups when alt tabbing out of Rust.
My GPU is a HD7950. Rust itself doesn’t lag as much though.

This boggles my mind. Yesterday I did a Fps test on 1920x1080.

Simple settings, all F2 options set to min/off.~40-42 fps.
Max settings, All F2 options on~22-25 fps.

My specs: Asus m5a99 MB/FX-8320E/Asus R9 270X OC, 16(2x8)GB Corsair vengeance, 1TB Spin disk :wink:

at first I thought it was instability because of my overclocks (I was only ~300mhz over factory for cpu, maybe 20mhz gpu) when it started a few patches ago, but since I reset to default clocks. Really hope this gets sorted soon, I honestly find it unplayable right now between current FPS performance and the crashes to desktop :confused:

WAIT---- Maybe it has to do with running dual channel memory or 2 sticks at least. I read a post last week I think on reddit and someone said he removed 1 of his 8GB sticks and he got much better performance.

How can we help Garry? Put me to work :wink:

Edit: By “simple settings” I mean “fastest” in launch, max settings was “Fantastic” setting.

I will try, however I’m not sure it will work. Will put my results in this post soon.

[editline]1st February 2015[/editline]

For some reason I think that this problem mostly affects AMD card. I don’t really see a lot of people complaining about their NVIDIA cards running the game slow.

Also, does anybody tested it with Linux to try out this problem? I’ll take a test drive today on Ubuntu, hoping that Rust on that OS might make a difference :smiley:

Same problem here.
4GB ram
I5 3.0ghz

Every time I look back or another player approach me, I get freezes for a few seconds. Trying to turn on PVT freeze the game indefinitely


Using Ubuntu it seemed that it ran A LOT smoother than on Windows 8.1. It used only 30% of my CPU, however the game still lags a bit on Ubuntu. I had 30 FPS on 1080p with lowest quality setting (on the F2 window, except my quality was set to Good). Using this same setup on Windows gave me 10 seconds freezing and 0.00000001 FPS. On Ubuntu there was no freezing like on Windows 8.1, ALT TABing was smooth, but the game was still kinda laggy tho.

I however still think the game uses my CPU instead of my GPU on Windows 8.1. Unsure why it works kinda good on Ubuntu.

Rust doesn’t really run very well on anything.

I do want to mention that this behavior didn’t apply for me in the past. I can remember running this game on Good without lag and certainly above 60 FPS, without any stuttering or freezing.

Ive noticed this also, I have my i3 overclocked to 4.2ghz and when sometimes my overclock reverts to its base 2.9ghz, the game runs like shit. Soon as the overclock is back on and PVT enabled it runs great.

Im running an old overclocked xfx 5770 as well.

System memory is 8gb.

These are my specs and i have 15-20fps

window 7 home 64 bit
AMD fx 4100 quad core
16gb ram
gtx 770 4gb

Similar specs 2 Aronk
AMD FX 4100-4130 Not sure
R9 270 Gigabyte Windforce 2gddr5
Windows 8.1 64 Bit
Major FPS drops after a long peroid, I end up using like 4gb of ram and 80% of my cpu

Sorry for the bump but this has to be fixed, so much people are affected by this bug and you basically can’t play this game for this reason. People that buy this game and see that they can’t play it because of the bad performance, obviously will write a negative review and that’s 1 less player…

It should be in high priority tbh

I can barely get 20 FPS on simple settings, with PVT on, on low pop servers. Change any of this data, I sink into 10-12 fps.


GeForce GTX 670M
Win 8
Intel i7
8 GB ram

I’m baffled as well.