CPU Bug "Limited by Main Thread" is causing the bad FPS

Hopefully, someone at Asobo, looks into this (a lot deeper than we the users can), and determines the optimum direction to take.

Its going to be a question of putting trust in ASOBO to do the right thing - and given resource limitations, I “have to” believe that that will happen – sooner or later,

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can we open a poll for kick out an alpha tester?

■■■■ it thx all for the info.

I don’t really see a problem listed specific to this issue on their problem list

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I have the same issue.

Especially when being on a runway my FPS is limited by the Main Thread.

On my machine (i7-10875h, Hyper-Threading turned off, 16 GB), 2 of the 8 cores are at 100% usage all the time where the remaining 6 cores are running low.

I thought that my limit is the GPU (RTX 2060, Full-HD) but in most cases it seems to be the Main Thread.

Does anyone know whether there are plans to fix this?

I recently upgraded from that exact same config to a 10600K paired with a 2070 Super, and a NVMe boot drive that’s big enough that FS lives there, too.

I actually tried to get another few years out of the 4790 by adding the 2070S first, but that didn’t work and I concluded that the 4790’s days were over and it needed to be retired. And that was BEFORE FS was even released.

You really do need an upgrade. You probably don’t want to hear that, because it sure isn’t free, and money doesn’t grow on trees, but it’s the reality of the situation you’re in.

I’m getting exceptional performance out of my new rig, even in the most adverse environments I’ve put it in for FS. Now, “exceptional” varies for flight sims as opposed to most other games, because even 30+ fps, as long as it stays consistent, will provide a good user experience. But on the games that need 60+, or 90+, or whatever, I’m getting it.

Hi, I’d bee curious you give the following a look and let us know is this is helping getting better fps on your system too, especially if you’re running in 4K:

I have the same phenomenon when my FPS becomes too low I save my flight, I exit the application and I restart it to return the initial and good number of FPS. I’m wondering. Would FS2020 be a memory leak?

Certainly sounds like it. It would be useful (to Asobo) to know whether this is in the main memory, or the VRAM - could somone keep an eye on Task Manager during one of the problem flights to see which fills up (if either)?

I haven’t seen this effect myself - this may be because my flights tend to be short, or perhaps because I’ve got 64Gb main RAM.

It really depends on resolution. At 3440x1440 I’m much more GPU limited than at 1080p or even 1440p.
Also, there is a big difference between 4790 and 4790k: 400mhz, and that’s without OC. I run 4.5ghz all core so that’s 700mhz more than 4790 all-core boost (3.8ghz). That’s a huge difference.

Once I get RDNA2/3080, it might be different. That said with the current engine limitation I think even with a 3080 my 4790k will not be 100% at all threads, but limited by main thread.

I’m familiar with that post, in fact I’ve bookmarked it and tried some of your suggestions, but haven’t had any measurable increases in framerates. I am not running 4K though, “just” 1440p. I haven’t done everything the same as you, though, probably most notably I have several things set on Ultra, and I have Texture Supersampling set at 8x8. I know that’s a pretty hefty performance cost, but I find it absolutely necessary for runway and airport environment textures in general, so I’m willing to make that sacrifice.

One thing I WISH I could crank to Ultra is volumetric clouds, but it’s just too much of a frame killer.

I’m getting similar performance than you, except when flying the Carenado Mooney (which I do almost exclusively since I bought it), which is costing me 10-12 fps over anything else I’ve tried, including the Baron. But that’s a Carenado issue.

I could have gone 4K for not much more than what I spent on the 2070S and monitor, but I would have had to sacrifice size and specs on the monitor end, which I wasn’t willing to do. (I’ve got a Samsung C32HG70.)

I’m also not convinced the averageish person viewing an averageish sized monitor at averageish viewing distances can actually see much of a difference between 1440p and 2160p, though the difference between 1080 and 1440 was stunning.

I actually tried running the sim on my 1440 monitor at 1080, it killed the visuals but didn’t make a lick of difference in the framerates.

I’m not sure if I gave you a good answer, it’s late and I think I rambled quite a bit, but feel free to ping me again if you have more questions.

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Thank you for the taking the time! I’ve significant fps differences between 4K and 2K with the 2070S and FS2020 in my experience. With the settings I’ve posted I’m very close to 60 fps in 2K and in 1K it is nearly stuck at 60fps and drops only on rare occasions.

I’ve find the key is balancing VRAM resources use, then adjusting settings so that you don’t over budget the CU with the shaders, which I’m trying to do with these settings. With a 2080(S/TI) you could push settings which are consuming CU (like 8x8 or clouds ULTRA) because there are more CU in the card. If you have more VRAM you could also push some other settings like draw distance/LOD (once the bugs are fixed and there is a user slider available).

I believe there are no good or wrong answers either because it is just so dependant on everyone’s systems and experience. There are just some technical variables we can ‘play’ with, share with each other and further refine configurations with the goal of achieving the best we can!

because not enough people are mentioning and voting the issue.

my single core is maxed out and im struggling for fps, i have heard that when they release DX12 this will help, really hoping it will be soon as im broke and can’t afford a new CPU I currently have a R5 2600x and 2080s and 32gb ram, i fel i would have a solid setup if the cores could spread the workload better :slight_smile:

Yes I agree, it’s unfortunate because I think the majority of people have the issue.

DirectX 12 may do that

They’ve already stated we shouldn’t expect big performance increases from DX12, mostly some more visual fidelity.

Thanks, I’m no expert but that seems to run contrary to most of what I’ve read and tests I’ve seen on DX11 vs DX12. Since the problem statement doesn’t appear to be obvious in what they give us, then what is their plan to address the main thread issue?

They’re already working on that, and have done some changes in the past.
The problem that lies in moving processes to other threads, is that the new process needs to be synced up with the rest, which is handled by the main thread. So while you’re able to offload some workloads from the mainthread, the syncing will put some strain back on it.

It’s a limitation of how things work in a sim. In a tile based renderer (like you’ll see in Cinebench) it doesn’t matter if one thread is done sooner than the others, so you can load all cores equally (and to the max), the final picture only needs to be ‘in sync’ after the whole rendering process is done. This does not work for a sim.

So yes, there will be more improvements in the future, and DX12 might help a bit, but it’s the nature of the beast that there needs to be a main thread that keeps everything in sync, and this will always be a limitation.

MortThe2nd, I think you may be wasting your time trying to explain that here. Far too many people seem to pick up on buzzwords (‘multithreading’ and ‘optimisation’ being favourites) and see them as some sort of magical incantation programmers use to ‘make everything faster’. Such people don’t like being told that coding doesn’t work through magical incantation, and that it instead requires understanding what the code is actually doing…

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meh, it might be, but if only 1 or 2 people pick up something from it, it’s worth my key-strokes.