The MSFS forum has thread, some (not all) users report fps will decrease over time on every single flight. Some posters there say it is a memory leak in MSFS program, and not an issue with a GPU being throttled back.

https://forums.flightsimulator.com/t/fps-reduction-over-time/436601/36

It happens with me, every single flight, always.

Rolling cache or turn it off: no difference. I fly on auto pilot for 20 minutes, 45 minutes, 90 minutes, results below displayed with ALT R as time goes by (the Nvidia Experience popup window). This window pops up in upper right while you are in a flight.

If I exit flight and start same flight again, fps stays low and keeps getting even lower.

If I exit MSFS and reboot and load the same flight, the fps is back up high again, like 33 fps. But will decrease as the flight continues.

Notice GPU is not getting hot it is cooling off, and GPU usage just keeps shrinking. Like I said over on MSFS forum people say this is classic case of a program 'memory leak' and that it came in with SU5. It started with SU5 for me too, never happened before in early update versions of MSFS.

It's really a slide show when fps that started high shrinks down to 10 fps for no good reason.

GPU usage goes from 100% to 27% to 20%. GPU temp from 75, 64, 55, GPU power wattage from 167, 67,50.

Every flight, every time, GPU less utilized as time goes by. Reboot MSFS resets it to normal high usage.

 

fps went from 37, to 12, to 10. Plane was just flying straight and level on autopilot for an hour and a half. It will happen on all flights.

I haven't had any problems regarding your posted issue, short or long flights, take-off to landing, frames remain the same

 

1 hour ago, CarlosF said:

I haven't had any problems regarding your posted issue, short or long flights, take-off to landing, frames remain the same

 

Same here.. two hour flights.. no issues..

Edited August 18, 20214 yr by Bert Pieke

no issues like this at all . last night 2.10 hours flight all went well FPS remain around the same . 

I completed a 3.0 hour flight yesterday.  However!  At one point upon entering a full IMC situation and a TRW, my frame rates fell from my spec'd 30 fps to under 20, and even as low as 11 fps.  I alt-tab'd out to my Corsair icue app to check temps and found no issues.  I took a restroom break.  When I returned I alt-tab'd back to MSFS and with the same conditions my fps was back to 30.  Go figure.  (Asobo has not fitted me with a restroom break sensor!)

Hmmm, some over on the other forum are just waiting and hoping the next update will fix the issue. No reason my GPU utilization should shrink like that. Starts out full bore, then even though there is no heating problem, the GPU throttles back. Exit MSFS and reboot MSFS and it's back to normal. Start a flight and down go the fps very gradually as the GPU stops doing its full thing.

I have only experience this in one flight since SU5.

3 minutes ago, Fielder said:

No reason my GPU utilization should shrink like that. Starts out full bore, then even though there is no heating problem, the GPU throttles back.

What happens if you set your fps to 30 in the sim?

Same thing if set fps to 30, it will ever so slowly shrink to 10 or lower after 2 hours.

I 'auto tuned' the GPU in Nvidia Experience (took about 40 minutes for it to run thru all combinations and tune it). Now I'm starting a new flight to see if that helps. Will take a half hour at least to test.

 

After 10 minutes the fps is not shrinking. Maybe the tune up helped. Also, I'm not 100% sure if I did have fps locked at 30 before, I thought I did maybe not.

I don't have a beast of a system just a gtx 1070ti, 16gbram, i7-8700k.  I do lots of 1-2 hour flights using Neofly flying all over the country. Fps stays around 30 (I have it locked).  I would suggest something else is going on to be dropping below 20, 10 or less.

16 minutes ago, Fielder said:

I 'auto tuned' the GPU in Nvidia Experience (took about 40 minutes for it to run thru all combinations and tune it). Now I'm starting a new flight to see if that helps. Will take a half hour at least to test.

 

personally i would suggest removing Nvidia Experience but that's just me (less programs running in the background the better unless it's proven not to hinder the system...it does on mine) .

Edited August 18, 20214 yr by Isaiah53six

Looks like fps is shrinking 😞 again.

Down from 31 to 25 , utilization from 100 down to 76%, fan speed from 3100 down to 2930, gpu temp is 76 (down from 80).

this is after 30 minutes.