One guy suggested a trick that works for him. In middle of long flight when fps tanks, land at closest available airport and shut off engines and wait the the 'your flight is over' window to popup. Then lift off again with fps reset to your regular high normal.

I had this issue with a long flight from EGLL to OEJN using 787 at 410' (no Mod) and clean comm folder, FPS dropped more than 60% during flight to landing, it could be something related to high altitude flights, haven't seen that with GA airplanes.

1 hour ago, Fielder said:

There are 138 messages in the thread below, most with the same problem as my original post. Dozens of dozens of people have the issue. Often I read: 'started with SU5'.

https://forums.flightsimulator.com/t/after-playing-a-few-hours-fps-drops-from-40-to-5fps/389603/141

This person here doesn't seem to have dropping FPS when they remove the add-ons from their community folder: https://forums.flightsimulator.com/t/after-playing-a-few-hours-fps-drops-from-40-to-5fps/389603/90

I suggest you remove all your add-ons in the Community folder.  Also, if you have any add-ons purchased from the MSFS marketplace, delete those add-ons too (an add-on is an add-on, even if it's in your Community folder or from the MSFS marketplace).  It's possible an add-on is causing this, especially because SU5 broke a lot of add-ons.

Test a long flight again without any add-ons and see if the FPS is stable.

 

Yes, I can confirm is a repeated issue, unfortunately, same here. Many of us, affected users like me hope for some kind of response from Asobo, I wish Asobo could be using the next update on August 24 for that.
To summarize, in my opinion, the common and main symptoms found, would be the next.
- More frequently after SU5 (many people experience that for first time).
- Appears in long-haul flights (2 hours and a half or more flights).
- Once happens the GPU stress goes below 30% - 40%. or more
- Frequently, (not always),  the FBW A320 (dev version) is present
 

i fixed it by turning ai traffic off then back on 

2 hours ago, FSUK_86 said:

i fixed it by turning ai traffic off then back on 

Makes sense to me.  Seems there was a similar issue in FSX but it has been a while.

Also there are a bunch more traffic out there now.

I have 32gig mem and don't pay much attention to usage.

Regards

bs

Edited August 19, 20214 yr by bean_sprout

Does it happen regardless of the aircraft you're flying? 

The DC-6 used to have a bug where frame rate would get gradually worse, until you clicked on the tablet and turned off and on the copilot / assistance thing, and it would pop back to normal.

Edit: I see it happens with a lot of different aircraft. 

It could might be related to the AI traffic bug. If it is, the good thing is that Asobo is working on fixing it. 

Edited August 19, 20214 yr by Republic3D

9 minutes ago, Republic3D said:

It could might be related to the AI traffic bug. If it is, the good thing is that Asobo is working on fixing it. 

Depending where you fly there could be 10x more traffic out there now if multi player is on.

bs

6 hours ago, Republic3D said:

Does it happen regardless of the aircraft you're flying? 

I completed a 3 1/2 hour flight today with the 172 G1000 and my frame counter never bumped off of the 30 I have it set to in the sim.  I was flying a relatively rural area and not near any considerable traffic.

DOH!

I think I got it fixed. I decided to alter Windows page file and do another boring half hour test. After watching memory leak away and performance drop from 28 at takeoff to 12 f.p.s. a half hour later. I got discouraged and landed.

Sitting on the tarmac, I happened to look around the cockpit and noticed all my dash lights toggles switches were twitching. As if a rough idle was slightly shaking the cockpit, like your keys hanging down when you're driving a car. They never seemed to change state. But they were, at a zillion times a minute. So quickly, it was hard to notice in the daytime.

Seems a few days ago I wanted to use a handy toggle on my Warthog throttle to turn on and off several specific lights at once, but not all of them. Problem was the WH toggle happened to be down and cycling them on and off. I had noticed these jiggling switches in the 172 I hardly ever flew the last couple days, and thought nothing of it. Just a feature I thought. DOH!

I unmapped those commands, the switches were stilled, and f.p.s. immediately shot up from 12 to 28 fps!

Which switch will you twitch? Probably none unless you are absent minded as me! 🤣

 

 

And I just tested for 35 minutes, fps when UP from 24 to 27, and gpu utilization stayed exactly at 100% the whole time, temp went up 80 to 81, and watts down 174 to 172, fan speed increased slightly. Stable, no more problem.

I think this was what is called a memory leak from bad programming (my bad programing in MSFS Controls).

All these exterior lights controlled by DX button 28 were jumping on and off and  were slowly leaking performance minute by minute down from 28 to about 4 fps after 2 hours. If your fps are leaking away, somewhere a programmed cat may be chasing its tail.

Interesting, thanks for sharing.

24 minutes ago, Fielder said:

I think I got it fixed.

I don't have constantly twitching light switches. But maybe the "normal" use of them has the same leaking effect as well over time. Indeed I played around a lot with my internal lights in the FBW A320 lately.

Will stay away from the light switches and see what happens.

 

On 8/19/2021 at 1:46 AM, Fielder said:

One guy suggested a trick that works for him. In middle of long flight when fps tanks, land at closest available airport and shut off engines and wait the the 'your flight is over' window to popup. Then lift off again with fps reset to your regular high normal.

This is the most ridiculous thing I've heard lol 

1 hour ago, Fielder said:

I think this was what is called a memory leak from bad programming (my bad programing in MSFS Controls).

I'm glad you fixed your issue, but I see lots of people both here and on the official site reporting variants of this problem, I doubt all of them have your controller, let alone your mapping of it.