Game Performance

[AmazingReflex]

I tested out my 3080 on ACC last night at 1440p. What is it with this game? I struggled to get any better than 75fps stable (looking at average fps, 1% lows was lower around 60-65fps). I was having to turn down settings making it look a bit rough in places.

Doesn't seem to matter what you have, it won't achieve high frame rates. Is this other peoples experience?

 

[Eng.]

Not really. I mean sure, *if* your CPU usage gets close to 100%, you are certainly CPU limited. But it doesn't mean you're not if it doesn't (and it's less and less likely to ever happen in gaming as CPUs get more cores/threads, but the games can't use a lot of threads and still mostly depend on 1-2 threads for their performance). Depending on the number of cores/threads your CPU has, you can be completely CPU limited while CPU usage is much, much lower. On my 12 thread CPU, you can be completely CPU limited with CPU usage around 8%. On a 32 thread Threadripper, you could be completely CPU limited with CPU usage around 3% - because if your application/game is single-threaded (or close to it), then once that single thread runs out of the CPU power available to it, it just can't get any more, even though the CPU might still have plenty left.

And it's frequently useless to even look at CPU usage for individual cores, because application threads tend to be "juggled around" very quickly over multiple cores and the end result of that is that you will frequently see CPU cores seemingly just chilling with no extreme usage on either, and yet the application thread will still be using all the CPU power it can get, you just won't see it manifesting on the individual CPU core usage.

So basically just ignore CPU usage for the most part, it's a fairly useless metric nowadays. Just focus on GPU usage, that one is accurate (for now). If you see numbers very close to 99%, your GPU is struggling. If you're lower, you can fairly reliably assume your CPU is the problem.

(And, again, given that he didn't see an improvement even at 1080p with a freaking 3080, the GPU is unlikely to be the issue.)

Multi core CPU can be affected like you said but I still think it can give you instant clue about the issue by CPU usage.

I think you are wrong about GPU usage totally. Unless you limit FPS, GPU usage will always be close to 100% to show max. FPS.

If GPU usage is low than 100% and you have low FPS, than again you should check CPU or memory usage.

 

[Case_]

Well, I tried...

 

[unpierrot]

You still haven't told us what CPU you have.
...

In another thread, he is getting issue with stuttering in AC and gives his config. PC (9900k, 32Gb 3600Mhz RAM, Samsung 500Gb 970 Evo plus NVME)

Game Stuttering

Update 04/12/20: I've added my last post to here so people see what the issue was straight away. OK, I think I've got to the bottom of why the game was locking up / frame stutter / slideshow effect. I've been doing quick testing just using an Xbox One controller over Bluetooth. Assetto Corsa...

www.racedepartment.com

Basically it's a powerful PC that shouldn't have that kind of issue.

edit: Perhaps looking at each driver (chipset, sound, video) and update with latest from motherboard site or manufacturer site could be a start.

edit2 : Beware, Windows 10 could automatically change driver with auto update. I was left without sound after that kind of unexpected update. Search the net, there's a way to avoid driver update with Group Policy.

 

[Case_]

(I can easily see even a 9900k being CPU limited in ACC under certain circumstances and with enough AI cars. Whether it should or shouldn't be is another thing.)

 

[Deleted member 197115]

Why do we keep talking "AI" cars here. AI physics is multithreaded and distributed across all cores, the rendering of opponent cars (AI or not) is what impacts single rendering thread and affects FPS.
Auxiliary load from physics calculations while adds load to CPU is usually not (separate threads).

9900k here, VR, never seen CPU bottlenecking with AI races.

 

[Case_]

Then you're running different ACC than I am. The AI physics might very well be multithreaded (but certainly not distributed across *all* cores), but it still tanks the game's performance a lot compared to just rendering non-AI cars.

 

[Deleted member 197115]

Then you're running different ACC than I am. The AI physics might very well be multithreaded (but certainly not distributed across *all* cores), but it still tanks the game's performance a lot compared to just rendering non-AI cars.

What CPU?

"The AI physics might very well be multithreaded (but certainly not distributed across *all* cores)"
How else multithreading works?

 

[Case_]

Ah, we playing the semantics game now. Fair enough. OK, technically it is being distributed across all cores/threads by the CPU scheduler, you're absolutely correct. Just not across all cores/threads at the same time, of course, since the game only uses around 4-ish application threads for the AI (and who knows what else).
But whatever. Have fun.

 

[AmazingReflex]

Sorry guys, I have a 9900k at 5ghz all cores, RTX3080, 32Gb G.Skill CL15 at 3600Mhz running game on boot drive 970 Evo Plus.

I think it's true, it's very hard to understand CPU usage with multi cored CPU's and game engine core / thread usage. When you look at the individual core usage of typical games they jump all over the place, never really maxing out anyone of them all the time so the reported usage can look typically quite low.

When I get the chance I will use MSI Afterburner and check GPU usage, VRAM usage and system RAM usage. Basically what we're saying is if GPU is maxed out then CPU limited. If VRAM at max then turn down quality / resolution. If system RAM at max then can be upgraded. I wondered if the speed at which the CPU can shuffle data in and out of memory was a limiting factor eg. RAM latency and speed or is this negligible effect?