Poor Performance with RTX 3080 and 3900X CPU " Limited by MainThread"

just read the article in the given links

So I tried this, with interesting, but not very helpful results.

Using your instructions, I disabled C6T2 from use by FS2020. It DID result in that thread no longer being pegged, and wherever that workload got moved to, it did not peg that thread, either. However, there was exactly zero change in performance. That was interesting itself, as you would think disabling 1 of my 12 available threads would result in decreased overall performance but it didn’t. Net result was that it neither helped nor hurt.

Interestingly enough, when I reenabled that thread, it did not immediately move that workload back to C6T2, as it did not repeg that thread and overall it appeared to be more balanced, but neither the overall utilization nor performance changed a bit.

Restarting the sim DID put the workload back on C6T2, but again, nothing I changed affected performance in any way, for better or worse. I don’t have the first clue what the implications of my experimental results might mean from a big picture perspective, but it was nonetheless educational.

Thanks for the suggestion, changing the affinity as you suggested was not something I was aware of, or would have thought of doing on my own.

KKT

pretty much what I was expecting, if there’s any difference between cores/threads, it would likely be too small for us to be able to notice (otherwise it wouldn’t have passed QC/binning at Intel / AMD.

Also removing one thread not affecting performance in a noticeable way doesn’t surprise me either, since it seems like MSFS is pretty happy with 4C/8T and up. If you remove threads to drop it below 7 available threads, I would expect to see a performance drop. The software is just (as designed) re-allocating workloads over different threads for optimal results (managed on an OS level, not from within MSFS).

Nice to hear your feedback after testing it though, it’s always fun to experiment when we have the time :slight_smile:

I know technical specifications of DX12 but it has nothing to do with this. Dx12 is used as a separate renderer and does none of the actual processing. Looking at links doesn’t change that fact.

Literally said here it’s not for performance:

Only thing which I heard is, that managers want held expectations low because they can not say when it comes ( which is not a wrong decision :wink: ).. and as I already say’d, other flightsim struggle with these change to dx12 a lot.

Other thing what I understand, as I scrolled throught, was that the PC-version is the Beta-Test for XBox release


I’ve got two systems, a Ryzen 5 2600 @ 4ghz with a 5700XT and a 10900k (stock) with a 2080S.

The real performance problems of stuttering and low FPS in dense areas and airports (JFK for example) are a huge problem on both systems. The max FPS is better on the 10900k, but the stutters, frame drops and overall low FPS is still there.
On both systems, performance is quite good when flying the bush trips. Those are low density areas using less demanding aircraft, hitting and maintain 60FPS with very little stutter and frame drops. Generally a good experience.

I have my doubts about throwing more money and hardware at the problem having any major impact. When the new Ryzen CPUs release, they might give a noticeable bump in performance, but again, they aren’t going to get rid of the core problem without major work by Asobo. Before throwing more of your money at the problem, at least wait for benchmarks.

Bottom line, the game just doesn’t utilize the CPU very efficiently and only they can fix this. Otherwise we are going to need multiple CPU generation leaps to make up for that inefficiency.

Watches OP’s video 


Hugs his 2080 Super

Thank you for this info ! Just one question. How do you set those various Vsync settings ? 1/3, 1/5 etc


In this “Hardware Unboxed” test on YT, pairing a RTX 3080 with a Ryzen 9 3950X or a Ryzen 5 3600 doesn’t make any difference in speed.

At 4K, MSFS seems to be having a capped framerate
 :woozy_face:

I’m not surprised at 4k games become more gpu bound, at lower resolutions games become more cpu bound.

I’ve seen more than 40fps at my system :wink: .. of course “only” 3840x1600 .. but no a 3080/90, just a “old” 2080Ti and much older i8700k

I’ve got a 3700X and 3080. Max every setting possible and set render scaling to 150 if on 1440p.

40+ FPS at all times pretty much!

yeah..

there a just million of useless test-report in the net
 and also, what much more important is as “FPS”, is “Not Stuttering”.. I would like 60fps , allways, in each flight condition, each airport, everywhere
 instead 200fps in 10% of the game

At the moment I am happy with 50% of the FPS that the Power machines get, with a modest gaming laptop that cost 10% of those Power machine 
 ( which will have outdated hardware by the time MSFS is running correctly ).

But if you have the money, and want the latest and greatest - good for you.
Credit Cards are wonderful things ( For the Credit Card Companies)

Exactly. That’s why I want to make sure u are GPU limited

You don’t understand how multprocessing works. One software thread (like the fabled MainThread) can only run on one CPU thread at a time. Depending on OS scheduling this thread may run all the time on a single core (showing it as “pegged” at 100%) or sometimes it is constantly moved between the cores for example to spread the heat (showing a 25% usage on each core if you have 4 cores). The operating system tries to run threads on their own physical cores if using hyperthreading. Hyperthreading may look like two full cores, but running two threads on a hyperthreading core maybe only gives 30% actual performance improvment even if monitor says 100% usage.

Still, one software thread can never use more than 100% of once cpu thread.

Also “usage” is not “performance”. 100% usage for two threads on the same core means that all resources of those CPU threads are now being used, but performance is depending on workload type.

I wanted to do some tests of my own . Can you tell me what airfield your video was taken over ?
I think 30-50 FPS is fairly good, i barely get 18 with a 1080 ti.

I would turn bloom off ( FPS hog) and grass and bushes down. Also contact shadows to 1536 and reflections to medium.

thanks

I notice you are in multi-player. Do you get better frames in std. play?

Have you tried turning off Hyperthreading (SMT for AMD chips)? I have a 3900X and 5700 XT on 1080p Ultra and when I turned off SMT, performance has increased on my end.

+1 :slight_smile:

the Vsync options are not “without thinking” 30 | 60 fps 
 same as later the xbox handles ( for PC monitors I whish me more options, but only because monitor sync, my 4k have not gsync ).. Have one heard that TV ( PAL , NTSC ) needs more fps than 25/30 (50/60 half) , or Blueray 24p , or or .. ? no, each people show each day hours of hours, without a fps diagramm..

We are just not in an ESL Counter-Strike match 
 the most users not notice a difference in >60fps , they just open the Game , then ask “how can I show the fps” and then make forum entry “I have only 59fps” :slight_smile: .. Each people have an own visibility range “of fps” and if your Eyes not told you “OMG”, then all is fine. In constrast to this, is Stuttering is much more worst thing


Thus, disable all these FPS tools and trust your eyes
 and not all of these marketing gags like 300fps monitors..

the other side is of course, that “Limited by Main-Thread” had can avoided with better programm-optimzation or not a usage of out-dated DirectX Versions
 Users which bought new expensive hardware in special for MSFS and notice now that this was more or less useless, are not so amused :face_with_hand_over_mouth: .