I have had similar issues since the update to 1.13.16.

My frames will drop to 4-5 fps and stay there for up to 3-4 minutes sometimes. 

I have experienced it all over the world, in a variety of aircraft, and at different points in the flight. For example:

-EGLC on the ground in the Carenado Mooney right as the flight loaded with a custom weather preset similar to fair weather.

-EGHQ, same as above except with the Carenado C182T. Plus during the cruise to Cardiff at 5500. 

-Cruising at 37000 with the FBW a320 between Australia and New Zealand. Multiple times on this cruise.

-Cruising over the USA in the FBW A320.

CPU usage goes down to ~20-30% and the GPU quickly jumps around between 10% and 40%. Very strange.

Up until this last update, I had no issues with the sim. Maybe 5 or so CTDs that were all related to addon aircraft. Nice and smooth. Strange.

Flight from KMVY to Montreal today in TBM930 - sim ran smooth for entire flight.  Before departure I checked framerate - it was at 30.  However, cruising at FL280 with cloud layer far below, rate dropped for most of flight to around 11 FPS!  BUT, it remained as smooth as silk - no stuttering, no pauses, nothing - just smooth.

I saw someone else post shortly after the update that there is a change with the sync settings - I will drop my sync setting from 60 to 30 for the next flight and see if there is any difference.

For me, it seems to be associated to specifically the "Online Functionality" option. 

On my current flight, I was experiencing this fps drop to 5 fps. I tested all kinds of things with no effect.

Then, I turned off the online options 1 by 1: Live Weather first with no effect. Live Real-World Traffic next with no effect. Then Photogrammetry and Bing Data World Graphics. Again, with no effect. I had all of them off except for the main "Online Functionality" and was still stuck at 5 fps. But, the second I turned off "Online Functionality," my sim returned to my normal fps.

Strange.

So we agree RTSS is no longer necessary?

VSYNC 30 in MFS and RTSS scanline -1 is the same?

The sim gets unplayable for me after some time. Around 2 hours into my flight while descending towards destination FPS started to drop from time to time and finaly went down to about 10.

I noticed that the "Applying Settings" screen after changing something took longer and longer with time. Finally i waited about 6 six minutes for a simple graphics setting to be applied. Had to close the sim shortly before landing due to low FPS.

Never ever had such issues before.

Specs:

i9-9000K, RTX3080, 32GB RAM, etc. Sim runs @30Hz

I have the same problem.
Yesterday i made a short flight, with average 30/35fps, and studdenly i have fps drop to 15/16 during few minutes.

I have the same issue. Locked at vsync 30fps in the program, GPU limited but hitting 30fps 99.9% of time except for these random drop offs with a main threw limit. I haven't figured out if it's because I'm loading a new area or not yet. 

 

Edit: sim is WAY smoother overall for me though. Most fun I've had with it. 

Edited February 21, 20215 yr by thegeneral101

6 hours ago, tomcatman24 said:

For me, it seems to be associated to specifically the "Online Functionality" option. 

On my current flight, I was experiencing this fps drop to 5 fps. I tested all kinds of things with no effect.

Then, I turned off the online options 1 by 1: Live Weather first with no effect. Live Real-World Traffic next with no effect. Then Photogrammetry and Bing Data World Graphics. Again, with no effect. I had all of them off except for the main "Online Functionality" and was still stuck at 5 fps. But, the second I turned off "Online Functionality," my sim returned to my normal fps.

Strange.

Exactly what I found. Online functionality off and the problem disappears instantly. Online functionality back on and instantly back to poor performance. Today during a 3 hour flight in the Carenado Mooney over Morocco I experienced the problem intermittently and each time turning off Online fixed it. The slowdowns mostly lasted a few minutes and went away.

I've considered that it's an issue with streaming, but when I experience the problem there is very little download activity. I suppose it could still be a streaming problem, just not caused at my end.

About 2hrs into a flight from KHOU to KJAC in the Longitude, I get the red manipulator, red mainthread and fps drop from a steady 30 to about 21. This continued for quite sometime with a very smooth 1000 or so foot Stratus overcast layer below me and about 2-3k agl.  I turned off the Online Functionality and things went back to normal, Turned it back on and it went back to red manipulator and now a purple mainthread.  Decided to push on through the 10-15fps decent and immediately once I hit that thin cloud layer, BAM!, completely back to normal. Not sure it was just a coincidence or if this thin Stratus layer caused the slow down. 

Forgot to mention that when the slowdown was occurring, going to clear skies did not help the issue.

yes it's the online function. I am seeing the same, running with good specs, and fps locked at 30, suddenly can jump into low 15's after the update and when switching off/ on online function,it's back to normal. I can get frames steady in the planes at 50 fps for hours.

I have found a fix that works for me on the official Forum:

If stuttering occurs open up the VFR map and pan around it a bit and zoom in and out. Fixed my stutters for the rest of the flight. Don't ask me how or why it works, but it does at least for me and some others.

Good luck!

5 hours ago, ThomseN_inc said:

I have found a fix that works for me on the official Forum:

If stuttering occurs open up the VFR map and pan around it a bit and zoom in and out. Fixed my stutters for the rest of the flight. Don't ask me how or why it works, but it does at least for me and some others.

Good luck!

Hard to believe but this worked for me on my last flight. Thanks for bringing this up.

Take care

Mick

This issue its getting more weird..

I am on MSFS main menu with ultra low fps ( 10 -13fps). GPU usage 6% and the only way to bring back the frames is to disable Online functionality. 

Something is holding back GPU, and i am not even flying or using the sim.

 

I have noticed this issue only if I have the multiplayer to all or something like this. I switched off the multiplayer and I kept only the real time traffic and I didn't see the issue.

1 hour ago, omarsmak30 said:

I have noticed this issue only if I have the multiplayer to all or something like this. I switched off the multiplayer and I kept only the real time traffic and I didn't see the issue.

never used Multiplayer, its always on OFF. Restarted and everything was ok. 

weird things...