I've submitted a ticket with the Forza support team - They closed it with the advice "This is a known issue and the Devs are working on a fix". So here is to hoping that the Forza team is doing as you described! :)

Unfortunately Zebulon, that's been the canned answer for anything wheel related for about 5 years now.

I would like to hope a solution can be implemented that doesn't punish the non Forza players. An optional download, something that triggers only with the Forza profile launch, a check box in the settings, "Forza Mode".

Forza is not a simulator, so any lag induced to correct the frame rate would be not be a compromise at all for the title itself. Infact, that's the biggest issue IMO with the glitch is that forcing a 60 FPS Vsync makes my input lag 70+ms when at full framerate and gsync on it's around 27ms. I doubt an alternate fix will be any worse than that.

My understanding is that FH5 uses the same engine as FH4, and Playground Games Studios couldn't take on a larger engine change (decoupling the physics from the render thread). From my communications with a contact in Turn 10 they are working on a different engine for Forza Motorsports 8 which would have this problem addressed.

I'm glad to hear that this might be the last version of Forza with this issue!

The semi-confirmed rumor is that Motorsport 8 will be the Unreal 5 engine. Depending on when it's released (probably this time next year) it will be the first racing sim on Unreal 5. No one has come out and officially said it's Unreal 5, that I'm aware of, but the job postings have all been for people with experience in that design engine.

On a side note, I messed with a bunch of processor affinity manual settings today in an attempt to make headway in this issue, including setting the GPU to use any of 24 available threads within a custom install of NVIDIA's driver's. I'm having a hard time confirming that this is the issue, or the only issue. Playing the game without AF2 plugged in, being GPU bound on water-cooled 2070 super uses a grand total of between 9-11% total CPU usage on my 5900x. Windows is confirmed to be using the proper AGESA scheduler from my BIOS for the processor cores, I opened up the GPU to use the closest available and it all changed nothing. Next step is to debug the USB input and output itself. 3 different drivers and a stand alone USB card didn't change it either. I'm leaning towards a serious mismatch in expected/supported FFB frequency between the wheel and game. I am yet to find a confirmed parameter for the game, was hopeful I would and it could be edited.

FYI @Bernard - I've passed the link to your post to my contact at Turn 10 and he will pass it on to Playground.

BTW, I'm not saying I disagree with your analysis of the problem, I may just not understand the concept well enough. Maybe what you are explaining could cause what I am seeing. If I understand the gist of it though; I think you are saying that the game design doesn't allow multiple cores to manage the FFB and or Video card, or both. I think that implies that saturation or threads or cores is taking place. That is what I am not seeing. In all of my tests and logs I never see any threads or cores even border on getting saturated. This game is not very CPU intensive, with the AF2 powered off I am GPU bound with only 2 cores or 4 CPU threads out of 24 threads. I can literally max out a 2070 super with 2 cores of a 5900x with this particular game. According to the in game benchmark, my CPU performance takes a 420% hit from just flipping the switch and powering on the AF2 during the benchmark. If someone does happen to get the ear of someone at turn 10, I hope these types of details are passed along. I just can't see this kind of impact being because something doesn't play well with multi-threading.

Here is a link to some test results from some windows performance analyzer recordings I did today. The big drop on the graph is turning the AF2 power off while in game, the rest of the pictures are the items that spike with the AF2 on and drop dramatically with it off. Most seen related to USB and HASH verification.

Hope this helps someone

https://drive.google.com/folderview?id=1Ys6lUms1iUgELSXaVFLoSnfaDtDntU7Z

@Robert - FYI - I passed this on to my Turn 10 contact (who should send this over to Playground)

Thanks Peter, hopefully something comes of some of my testing. I'm running out of ideas, Haven't even played the game since about the second day. I consider it pretty much unplayable at this point, I even submitted a request for a refund. I was doing some USB Wireshark testing recently and the update rate is absolutely staggering, If it is choking the game engine, I don't think a game-side fix is possible, without maybe the addition of the wheel and it's parameters being added to the game as a recognizable and pre configured wheel option.

I'm not sure if it's possible with the AF2, but I know that some other DD wheels have a setting to adjust the update rate of the wheel, that would solve the problem without a separate driver, I'm pretty certain. A game like FH5 doesn't need and probably isn't at all designed for a 500 full duplex FFB operations per second, even more communication takes place if SC4 is connected to the game. One way to confirm this theory would be if anyone has a PC or USB hub that is UBS 1.1, I dug through all my goodies and found about 3 USB 2.0 hub's, but no 1.1. The thought behind this is reducing the polling rate from a maximum 480mbps equivalent to 12mbps will cut the update rate significantly at the hardware level, thus reducing the saturation of the game, driver or whatever it is that can't seem to take the update rate it is getting. If anyone has a USB 1.1 hub, please just use the wheel through it and let me know the results.

"even more communication takes place if SC4 is connected to the game" - That is for the most part incorrect. Sim Commander uses an entirely separate interface for its communication to the AccuForce. There is the standard interface and the interface used by Sim Commander. Each can run up to 1000Hz and these can be ran simultaneously.

"'m not sure if it's possible with the AF2, but I know that some other DD wheels have a setting to adjust the update rate of the wheel, that would solve the problem without a separate driver, I'm pretty certain. " - I'm afraid that's not the case. If we slow down our polling rate then it would only make the problem worse because each time Forza sends a command, it would taker eve longer to complete.

Here's to hoping for a fix in the next version!

Bernard, I'm speaking about traffic from a purely physical interface perspective. I was using USBPcap and Wireshark to log all the interface traffic, primarily looking for differences between FH5 and games that work well and FH5 FFB enabled and not. I didn't break it down by logical interface, but I could see the additional, larger transfers with SC4 running, they have like a full profile list of capabilities in each transaction.

Hopefully there will be a fix at some point, I have a different impression of the issue than you do though, I can't imagine the game is requesting more updates than the 1000 per second that 1000hz is capable of, or I'm assuming 500 in 500 out. Maybe there is just to limit? No cap? That might make sense, if it will request as much as your CPU is capable of asking for? It seems like a tremendously inappropriate amount of transactions for one reason or another. I did see requests and replies becoming separated by 4-10 transactions with the game running. The other noticable difference was the data format between in and out, they seemed to almost be different HASH's or HASH bit's between the wheel or game data. Anyway, long story, but I just don't know enough about HID, USB and the like to know exactly what I am seeing. I think I'll be able to test my hardware throttle theory tomorrow though, Amazon had a trinket that I believe will do the trick.

To the best of my knowledge, the bug, as I described it in the document below, was acknowledged by Forza and will be corrected in the next version. Granted, that was also said about the previous version, but we have to cut them a little slack. That development occurred during COVID and wound up being the same engine with new content.

https://www.simxperience.com/slides/slide/why-is-forza-framerate-lower-with-a-dd-wheel-93

If enough people want to compromise performance in other games to have this, we would certainly do it. It's not an optional thing as some have suggested though. We can't have it both ways.

Well, worse case if enough people want it; couldn't it just be an option download on the site? I.E. a dead end fork in the road. Forza players could download that version and weight the impact on other titles, judge for themselves to keep it or not?

It doesn't make any sense to create a permanent impact on every title for the benefit of 1 title, although since I'm not a hardcore sim person it wouldn't bother me, it would still be completely unfair to push a lesser package to everyone.

A dedicated Forza driver as an optional download would be great. If there was such a driver i would install it.

It sounds to me like a "Forza Mode" would just mean a driver that is optimized for Forza, but hurts performance on other sims. I don't want that. I sim with triple screens, and that would kill my performance. On some sims, it's pretty tight already.

My comment here may be irrelevant to this topic, or solving for a different issue, but thought I'd post anyway.

My PC was having similar problems with Forza Horizon 5 stuttering and getting FPS in the low to mid 40s on a 4k TV, regardless of resolution or graphics options. This started for me in February after having no issues before that, and I had assumed a Forza monthly update caused the issue and shifted to other games.

Well I started looking into recently, and after doing research elsewhere on FH5 framerate issues without results I finally looked on the Simxperience site. Robert's comment about USB was something I hadn't considered, so I changed the connection of the Accuforce control box to my PC from UBS 3 to UBS 2. That fixed the issue for me!

I did change Accuforce's connection to my PC from UBS 2 to UBS 3 earlier this year when dealing with an unrelated issue and forgot about.

I read the whole thread and most of it went over my head. My FH5 set up now may still have the lag issue, but for achieving a 60 FPS situation where steering seems more true to life it seems to have worked.