Massive drop in FPS in just a couple of laps. What is wrong?

Hi.
Need help to figure this out. Massive drop in FPS just in a couple of laps.
Start with 300 fps drops to 90 fps and the game is stuttering mostly noticeable when cornering.
I play other racing sims without any problems.

I run release v 1.31.01912.

Any suggestions or is this not fixable without another update?

 

You have a problem, but all info you give is fps and game revision.
Thats to few to analyse anything.
Please add your specs into a signature ( e.g. like mine ) to know what we're talking about.
Madness engine is very demanding on GPU, you shouldn't overclock it if you do.
Check temperatures of GPU and CPU, maybe you reach heat where this parts begin throtteling.
Check taskmanager if there are unneeded apps stealing CPU/GPU
Disable steam downloads while gaming
IF you have massive drops, did you try other track & cars. Report on what session settings it happend.
Report your ingame settings.

 

Sorry my bad.
- I wrongly asumed it was a well known issue since it's been around since projects cars 1.
(same madness engine)
The accepted work around for projects cars is to cap the FPS to 62,8.
Not OK according to me.

I verified this problem on three computers.
1. cpu 9900k gpu RTX3080
2. cpu 8700k gpu RTX3080
3. cpu 8400 gpu RTX2080ti (works better on this one)

No heat or other interfereance to performance.
I belive this is an Automobilista 2 issue, inherited from project cars 1 and 2.
But I will also check if there is any throtteling or Nvidia releated problems.
I have been known to have wrong before

Ingame settings don't effect this issue.
Right now all settings is on low or turned off.

My experiance is that this is not solved with the latest release v 1.31.01912.

Try Oulton park international.
-Note the starting FPS and compare what you have after three four laps.
Also look for micro stuttering when cornering.

 

I have those microstutters in some corners on some tracks since the game was in early access on two different PCs. Still couldn't find out how to fix it or what's causing it.

 

From rivatuner statistic server:

CPU usage around 15-20% temp around 55 C
GPU usage at start 97% temp 52 C when the FPS drops the GPU usage drops.
At start 97% after 4 laps down to 28% !

- So the GPU usage follows the FPS drop and the micro stutter also gets worse with lower FPS.

Rivatuner from AMS2:



Something is not working correctly.. but what?
Can't find any problems with my computers.
Also all other racing simulators runs fine.
Even project cars 2 is smoother.
-Have a look at the GPU usage for example.
(Track Oulton park international on both)

Rivatuner from PC2:




I'am convinced this FPS drop and stutter is an Automobilista 2 issue.

Also found two older post on the same topic, no solution to them either:
Post 1
Post 2

What is triggering this problem?
AMS2 and ?

 

Answering my own post..

Found the root cause of the problem.
The lead to this was all the post with people having problem with wheels and pedals.
And the final clue was this post: Final clue

Automobilista 2 has a broken "control module" for wheels.

I tested the following with my Fanatec DD1.
Tried different settings for the wheel within AMS2.
Depending on what wheel profile chosen the FPS and the game behaves differently.

-legacy stable fps around 180 but bad stuttering not playable.
-CSW 2.5 Super broken FPS, and around 40 after just a couple of seconds and the game falls apart.
-DD1 start at 300 fps drops to 90 fps and the game falls apart.

And finally drove it with only the keyboard.(No wheel enabled)
Guess what:
- It worked flawless !

But i want to be able to use my Fanatec DD1 steering wheel so.
- Please look into this Reiza.

 

Have you tried using different USB ports? In case it's a USB hardware/driver issue?

 

@Erling just out of curiosity what type of usb port are you connecting to and do you have USB selective suspend disabled in your power plan? I had a similar issue with fps drop-off when I accidentally reset my power plan without realising.

@logos post in the thread you linked to was super interesting as well. I had no idea there was a difference in update rate from profile to profile, always just assumed it was mostly about button mappings.

 

@azaris yes thanks for the tip thou (even verified with different computers).

@chonk Tried USB 2 and USB 3 same strange behavior from AMS2. Have not changed anything in the power plan. This is an AMS2 issue. That need to be adressed by Reiza to be resolved.

 

Made a bug report here: Bug report

 

Discovered an even bigger bug.

- When I turn off the FFB set gain to 0 the fps doubles.
And the game works without stuttering.

-If I turn on force feedback with gain 1 or bigger the fps is cut by half and the game starts to stutter.

How could this go on unnoticed?

Is it only on my computers this happens?

Bug report here: Bug report

 

Sounds like your DD1 might not be able to keep up with the 600 Hz update rate of the FFB (no clue why). Could you try reducing the FFB rate by adding a command-line option "-ffb xxx" where xxx is somewhere between 100-600? This was a parameter in PC2 that you could change but I'm not sure if it still works in AMS2. Should be a quick test just to see if it makes any difference.

Also check your firmware version, some Fanatec drivers in the past had bugs that caused massive stuttering iirc.

 

@azaris That's what the profile setting does in AMS2, changes the update rate.
The wheel work fine in project cars 2 and all other sims.
I have Fanatec's latest driver 429 with wheelbase firmware 689 motor 41.

I run an diagnostic tool and found that AMS2 is spamming dinput8.dll
which in turn talks to FAWForceFeedbackDrv64.dll.

dinput8.dll (windows components connected to force feedback)
FAWForceFeedbackDrv64.dll ( A Fanatec dll)

Over time dinput8.dll gets more and more resources.
My best guess is a buffer of some sort that fills up and never gets flushed.

-This leads to overload and the game stutters.

It actually does more than stutter the input lag eventually gets so bad you can't control the car.

 

What force feedback profile are you using? Is the performance different if you try Default / Default+ / Custom ?

 

@Roar McRipHelmet Thanks for asking, Tried all three same issue. Drops FPS and both GPU and ECU are more or less idling. When logging one can see that dinput8.dll gets more and more occupied and GPU and ECU load gets less and less.
Do you know the difference between these settings, under the hood so to say?
(Default / Default+ / Custom)

No change since latest patch : V1.3.1.1

 

I don't know if there are any specific differences, but I had this quote from the November Development Update in mind:

 

@Roar McRipHelmet Clear as pea soup

- Hope Reiza is fixing this FFB issue soon.
I thought from the beginning that this was something inherited from project cars, but
it is not. This is something Reiza have messed up all by themselves.

Shall see if my son can help his father and write a little program that prevent AMS2 spamming dinput8.dll. Not sure if it works, the issue can run deeper in the code ..
But maybe worth a try.
(as a work around until this gets solved)

Tested a first version of a work around:
AMS2 can only 10 x SetParameters in 10 ms
PC2 sets 62 x SetParameters in 10 ms
Both starts around 60x SetParameters in 10 ms but in AMS2 this gets slower and slower.
- SetParameters is part of the data stream to FFB.

Just need to find where the data is clugging up...

Ok found that PC2 is limiting the data stream to FFB to every 5ms.
PC2 also have an effect called SINE that is removed for AMS2.

AMS 2 just sends data as fast as possible, this is most likely the culprit.
But there is probably something more, we have not found yet..

This also seems to have an strange side effect.
- With low graphics settings the FFB is the limiting factor for FPS.
(at least with a fast card like the RTX3080)

 

@Erling
PC2 would send FFB with ~180Hz-200Hz rate, while AMS2 ~400Hz-600Hz rate, which normally shouldn't overload the usb subsystem. Also hardware vendors make sure to limit the rate of output HID reports in the drivers to appropriate for the connected device levels. For a Fanatec DD wheel, they are probably limiting it to >=1000Hz, as it is very responsive device with an ability to execute commands on a sub ms level, without ever blocking the bus.

I have a similar system like yours (although previous generation), and can use my SC2 Sport with AMS2 or any of the other sims without any problems. In fact AMS2 is one of the most fluid and responsive sims on my system. I play mostly on Linux with Steam Proton/Wine and have even higher FFB rates with AMS2 there. For example on Linux the FFB rate is ~500Hz-560Hz, while on Windows it is ~400Hz. The gameplay is very responsive without any stuttering, and with FPS above 100 on Ultra in pretty much any track with thunderstorm and the max number of AI.

Your signature indicates that you are using a Valve Index Headset. Did you try to disconnect it from the usb ports, and use the monitor for a test. The VR Headsets use huge amounts of bandwidth, which could hinder the performance of the whole bus and the devices connected to that particular controller. If your system allows it, use the HMD with a USB port connected to a separate controller, than the other usb ports. On my system the USB-C port is controlled by a separate controller, while the other USB ports are connected to the Intel chipset.

Something is blocking your USB bus when the frequency of HID Output reports go above a certain level, which is unusual for a system like yours. Aside from hardware problems, It could be caused also by drivers - Nvidia, Fanatec, Valve, etc. Or even the Windows installation, which stores references in registry to any HID device ever connected to the system, and sometimes could mess the things up.

What Reiza could do here is to put an additional field for the FFB rate in the controller setup, similar to ACC, for example. This would allow people which experience usb problems to limit the rate to levels which doesn't hinder their systems. While allow the others esp. with DD wheels, to use as higher as possible FFB rate, which is of great benefit to their wheels. The more the FFB rate on a DD wheel, the smoother and detailed the feedback, the less reconstruction and damping needed.

 

@logos Thanks you for responding to my problem!
The only USB device i have connected on the computers is DD1 with the pedals and the H-shifter connected to the wheel base. Even the mouse and keyboard is disconnected.

The FPS and the usage in the GPU is high the first couple of seconds then it slowly starts to drop.
Look at the screenshots earlier in this post (logged with rivatuner).
We made also a profiling with Visual studio. It shows that AMS2AVX.exe is spamming dinput8.dll.
dinput8.dll is getting more and more resources and the stutter gets worse and worse.

This only happens with AMS2 no other SIM.

But just to sure that the USB ports on the MSI Z390 or the drivers for them is OK.
I will change to another board. And yes it's soon time to switch over to Linux

Updated bios on the Z390 reinstalled windows 10 = works fine
Made a program that spammed the DD1 at 1000Hz. = works fine.

AMS2 = Still same problem
Spent to much time on fault tracing, time to watch some F1 qualifying.

 

I’ve been scratching my head at so many people experiencing stutter and fps issues, I don’t have much technical knowledge of this stuff, but haven’t experienced any of these issues with my medium level pc set up, and it’s very much Gpu bound .
I always run custom ffb and have most performance settings on ultra or high.
I have my fps capped inside rival tuner to 90 , but it will run lower if lots of cars or challenging weather.
But I’m not getting stuttering .
I’m currently running Udp off , as I have no need for it to be on, and I’ve gone through the control panel and other settings to ensure system optimisation for bias towards performance and gameplay etc. making sure any USB devices aren’t power saving etc , but that’s it really.