CPU and GPU not fully utilized...Why?

Duderei

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Hello fellow racers - For the longest time I had an issue with one CPU going strait to 100% even on low GPU settings. Changing a whole lot of settings I managed to resolve that and had very nice results with my 1080 TI being used by at about 90 to 92 % during online races.

Not sure what changed bot I have the issue that my GPU uses is not going passed 40% anymore resulting in low FPS again, however checking all CPU Cores, none of them is even pushing more than 55%. I have been changing and testing settings again, but I cannot make it use the full CPU power anymore.

Any tips what I can do to get that fixed?
My System is a 3770K @ 4.4GHZ with a GTX 1080 TI - I didn't change any hardware so why is AC not using it anymore?
 

RasmusP

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The topic is quite complicated, if you search for single thread limit and have a look at my posts in cpu/gpu related threads (sorry can't be bothered to link them from the phone) you'll get some more in depth explanations.
In short: the old behavior was more "true" with one core sticking at 100%, which was your single thread limit.
Now Windows got some tricks so it splits even single threads into small pieces and let each core process one of the small pieces one after another. Overall you gain quite a lot of performance but it doesn't change the fact that it's still one thread that can't be processed in parallel!
My favorite imagination of it is that you got one big nail that needs to be put into a really thick wall.
Instead of one guy hammering like crazy and the rest of the group just standing around, windows let's each guy hit once as hard as it gets. But everyone getting his own, smaller nail would still be a lot more efficient.
Sadly you can't split a lot of things into parallel pieces. You can't process tyre behavior before the steering input etc.

If you download the little tool called process explorer, right click on the acs.exe and go into properties - > threads, you'll see the cpu usage of each internal application thread. The maximum one thread can take is 100% divided by the amount of (virtual) cpu cores. So for an i7 it's 100/8=12.5.

There's no way to make assetto corsa use your cpu better/to more extend sadly.

Hope that helps :)

BTW to quickly check whether you are cpu or gpu limited just check the gpu load. If your 1080 ti isn't utilized to 99%, it's either a fps limiter, your 1080 ti running in 2d mode or, like most of the times, your cpu.
 

Duderei

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Thanks for the quick and detailed answer. Following your tip, this is what I see.

upload_2018-12-16_16-30-17.png


I assume that is the 12.5 in Theory so I am right there. That also means the only thing to do to get frames up is figuring out which setting is filling the thread again since I had way better results before something (unknown) changed.
 

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RasmusP

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Thanks for the quick and detailed answer. Following your tip, this is what I see.

View attachment 281808

I assume that is the 12.5 in Theory so I am right there. That also means the only thing to do to get frames up is figuring out which setting is filling the thread again since I had way better results before something (unknown) changed.
Most cpu related fps eaters are reflections (refresh rate, not map size) , reflection and mirrors rendering distances (only in content manager or ini), world detail and amount of AI cars.
By far the most fps eaters apart from settings are the hud/apps! My preferred leader board app "substanding" drops me down from 100 to around 65 fps during online races and makes them drop to sub 60 fps at race starts.
So maybe check if you installed any new apps!

Also these shader patches with rain and night etc etc are definitely not only heavy on the graphics card but I guess you would remember if you'd installed them :p
 

Duderei

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You pointed me in the right direction. I just turned off all of my Apps. Even though not many the FPS drop they are causing is unreasonable. I am now back to just using Helicorsa and Games more than double the FPS than before.
 

dud

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Nov 23, 2016
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Is there an equivalent to Linux/FreeBSD's top(1) on windows, which will give 100% for each core's max, so you can easily see whether some random process has a single core maxed out?
 

RasmusP

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Is there an equivalent to Linux/FreeBSD's top(1) on windows, which will give 100% for each core's max, so you can easily see whether some random process has a single core maxed out?
Absolutely no idea but it sounds great!
 

RasmusP

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https://www.racedepartment.com/threads/enhanced-aa-settings.106893/

I think Rasmus means this article. May be wrong, he has contributed loads to these forums.

I got some very good information from this article.
There's some good info for sure I think, thanks :)

Regarding CPU performance and all this single vs multi thread stuff I honestly can't find my old posts with the full explanation but the short version with the hammer, nail and too many hands was a good summary...
If you want to see how different the CPUs scale across old games that might only use one single thread vs rendering programs or games like F1 2018, Assassin's Creed and Battlefield (although these games are still at 1 big thread and 3-6 smaller threads) you can read from my post here going on:

For your info, Raceroom, Assetto Corsa, rF2 etc are all more or less on 1.5-2 threads. So the real performance will be between close to 2 threads and 3 threads in the charts :)

https://www.racedepartment.com/threads/intel-9th-gen-cpus-revealed.160339/#post-2850242

I'll link the most important images though:


(2600k = 50 fps all the time, rest accordingly scaled)

A summary about performance, prices and my recommendations can be found here:
https://www.racedepartment.com/threads/intel-9th-gen-cpus-revealed.160339/page-3#post-2851955
 
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