Repeatable performance bug - Restarting a flight drastically improves FPS and frametimes

Bug Reporting Hub Install, Performance & Graphics
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Yes

Brief description of the issue:

I start a flight in my Bonanza G36 over NYC @ 1500 ft. AGL. I see around 35 FPS and around 35ms latency. If I hit ESC, then Restart the flight (not the sim, just the flight) I immediately see 50 FPS and 22ms latency. This is repeatable. If I restart the sim itā€™s back to 35FPS, and when I restart the flight performance dramatically increases.
(Iā€™m actually hitting around 65FPS / 15ms now (due to some additional system tuning) but the bug is the same. Poor performance initially, followed by a dramatic increase on flight restart.

Hereā€™s a link to a long troubleshooting thread Iā€™ve been working with.

Provide Screenshot(s)/video(s) of the issue encountered:

CapFrameX_Bonanza_NYC_Lasso_Bitsum_HAGS OFF_Game Mode OFF - Pre-Sim Flight Restart
CapFrameX_Bonanza_NYC_Lasso_Bitsum_HAGS OFF_Game Mode OFF - Pre-Sim Flight Restart1517Ɨ1216 80.7 KB

CapFrameX_Bonanza_NYC_Lasso_Bitsum_HAGS OFF_Game Mode OFF - Post-Sim Flight Restart
CapFrameX_Bonanza_NYC_Lasso_Bitsum_HAGS OFF_Game Mode OFF - Post-Sim Flight Restart1544Ɨ1226 76.7 KB

Detailed steps to reproduce the issue encountered:

I repeat the same flight over and over: Clear weather preset, 1500 AGL about 10 miles east of NYC, fly west over the city @ 130 knots. 5 minute data capture using CapFrameX.

Many issues may be due to an outdated graphics card. Please state your Graphics Card Driver Manufacturer (NVIDIA, Intel, AMD) and Version (Learn how to find your current graphics card driver version):

nVidia 3090 Ti 24GB, driver v. 556.12, DX12, DLSS DLAA

9/9/24 - DDU uninstalled driver 556.12. Installed latest 560.94
Tested - had same result. Low FPS, high latency. Also, G1000 PFD and MFD were powered OFF. Immediate flight restart resulted in much higher FPS, much lower latency, and normal G1000 screens

PC specs and/or peripheral set up if relevant:

AORUS X670E Pro X, 7950X3D, 2x32GB (64 total) DDR5-6400/CL32, nVidia 3090 Ti/ 24GB VRAM

Build Version # when you first started experiencing this issue:

What ever the most recent build is.

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Do you have the same issue if you follow the OPā€™s steps to reproduce it?

Provide extra information to complete the original description of the issue:

If relevant, provide additional screenshots/video:

2

Do you have the same issue if you follow the OPā€™s steps to reproduce it?

yes

Provide extra information to complete the original description of the issue:

I have noticed this behaviour for at least two years.

My routine practice has now become:
(a) set up a flight,
(b) try it briefly,
(c) see several problems, and
(d) immediately restart at least the flight but sometimes the entire sim, and usually then have an enjoyable flight with performance as expected. Rarely it takes two or more restarts.

This has become so regular a habit now that I had accepted it as one of the little annoyances of life. It is particularly noticeable after a Windows update or a GPU driver update, or even a few days away from the sim.

If it can be found to be a ā€œbugā€, then whoopee!, letā€™s fix it! But MSFS 2020 has been full of inexplicable little annoyances has it not?

If relevant, provide additional screenshots/video:

1 Like
3

It never even occurred to me to try restarting either the flight or the sim. The recent upgrade to the 7950X3D is what prompted the discovery for me. Performance was not what I had hoped for when I started my tuning journey.

I normally donā€™t repeat the same flight regime 20 times in a day as I test different variables. During my testing I noticed the variability (35 FPS one flight, then 55 the next) even when nothing had been changed. Thatā€™s when I discovered the bug, and the repeatable restart band-aid fix.

Iā€™d love to know whatā€™s causing it, and I certainly hope it doesnā€™t carry over to FS2024.

2 Likes
4

Do you have the same issue if you follow the OPā€™s steps to reproduce it?

Yes,exact the same here

Provide extra information to complete the original description of the issue:

If relevant, provide additional screenshots/video:

6

Thank you all for your reports! Iā€™ve now feedback-logged this item for internal review.

The MSFS Team :slight_smile:

3 Likes
7

Good its logged, but i couldnt reproduce this on my end.

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The biggest problem with reporting ā€˜bugsā€™ on the PC platform is that every PC is different.

3 Likes
9

Those of you who can reproduce it, have you tried doing so with all traffic disabled? Iā€™m wondering if itā€™s a case of traffic not loading properly the second time, or causing a memory leak in the first one.

10

I did a flight over the Sahara yesterday, and did not have the problem. A subsequent flight over NYC did. I wondered whether photogrammetry might be an issue. Iā€™m going to test with that disabled. Iā€™ll test with traffic disabled as well.

1 Like
11

Canā€™t reproduce this on my end either. The performance is exactly the same before and after.

The only thing that restarting a flight resolves on my end is when certain instruments donā€™t work. The transponder is known to not work (unable to switch on) on some aircraft unless I restart the flight. And the other day the lower three screens on the TopMach F-22 wouldnā€™t turn on until I restarted the flight.

12

Interesting. I didnā€™t mention that I had the same thing happen in my Bonanza a couple of times. The G1000 PFD and MFD started mid-air turned off (the MFD showed the Garmin logoā€¦ When I restarted the flight they were both on.

13

No turning off on my end. They just donā€™t plain work from the get go sitting on the apron cold & dark. I canā€™t switch them on when I power up the aircraft. If they do work, however, they never stop working.

Itā€™s also relatively rare. Most flights start out fine.

1 Like
14

Do you have the same issue if you follow the OPā€™s steps to reproduce it?

NO

I havenā€™t made any drastic changes to my OS W11 pro. Iā€™m always using the latest drivers and BIOS.
MSFS settings are set to Ultra 2K with TAA and DX11, traffic disabled. Below is my hardware configuration:

  • MSI MAG X670E Tomahawk WIFI
  • Ryzen 7 7800x3D
  • 32GB DDR5 7200
  • RTX 4090 Gaming OC
15

Info added to bug report.
I updated to the latest nVidia driver (560.94)
Did not fix the problem.

1 Like
16

This link to my troubleshooting thread added to Bug Report. Iā€™ve tried everything I know to try. I believe this is a bug. Itā€™s a 100% repeatable problem in the areas in occurs, and a 100% repeatable non-issue in the areas it doesnā€™t.

Iā€™ve tried everything I can think of (and many things other helpful members thought of) and have not been able to resolve it.

17

Rereading this thread made me realize that with all the troubleshooting Iā€™ve done on this problem, Iā€™d never tried your suggestion.

Sure enough! I think you nailed it!

I turned all traffic OFF, and there was no longer a discrepancy between first flight and restarted flight. Eureka!

I slowly added Traffic in (other than Aviation Traffic, which I left OFF) and the discrepancy had disappeared. Flying over my problem areas (NYC, Washington, DC, and KDFW) I found that the FPS was the same (around 70-75 FPS) both before and after I restarted the flight.

Adding Aviation Traffic (even when set as low as 10%) immediately brought the problem back.

This is obviously not ideal, and itā€™s definitely a BUG. I think you found the root cause. Thank you.

With the settings below, I would get 45 FPS flying directly over KDFW. Then when I restarted the flight, I would get 70 FPS. When I turned Aviation Traffic OFF, Iā€™d see 70 FPS right away.

Traffic Settings - FPS Bug
Traffic Settings - FPS Bug1920Ɨ1009 96.8 KB

2 Likes
18

Can you please review my last post in this thread? I think we found the root cause of the problem.

Thanks

19

5 days ago :wink:
https://forums.flightsimulator.com/t/repeatable-performance-bug-restarting-a-flight-drastically-improves-fps-and-frametimes/654184/14?u=tenpatrol

20

Further testing confirms that the bug occurs when AI Offline Traffic is enabled.
It does not occur with Live Traffic enabled.

21

It would be interesting to know
a) The number & model types being spawned with Live & AI Offline traffic in order to determine if there is a model or models used either exclusively or more frequently in Offline mode.
b) If changing settings for ā€œUse Generic Aircraft Modelsā€ and / or ā€œTraffic Varietyā€ makes any difference.