I have found that my abnormal poor destination or long flight performance has something to do with the Vsync 30 setting.
As I approach my destination and the performance drops, if I disable vsync, the performance returns to normal, I can then re-select Vsync 30 for the remainder of the flight or landing with full performance as expected.
It’s as tho something is building up over time while Vsync 30 is enabled. Toggling vSync seems to clear the baclklog.
Vsync 30 means it limits your FPS to half of your monitor’s refresh rate.
The game developers implemented the FPS limiter as a simple Direct3D flag which tells how often to present a new frame – every 1 or 2 or 3 refresh cycles. Should this cause any degradation of performance in long flights? Absolutely not. But your experience indicates otherwise.
Do you have any screenshots? for example the fps at the departure and arrival airport. Then the fps after toggling vsync, which shows the FPS is back.
Try RivaTuner Statistics Server fps limiter. That’s what I use. It’s a true CPU wait-based limiter instead of a simple DXGI method parameter. I never noticed any performance degradation using it. Just make sure the FPS limit you set factors evenly into your display’s refresh rate.
Another alternative is to try your graphics driver’s built-in fps limiter.
I found the early implementation of the MSFS native fps limiter introduced massive stutter, but later releases were incredibly smooth. I didn’t find the RivaTuner or nVidia limiter to have the same degree of inter frame consistency (for want of a better term). I will take another look. The effect on the performance degradation might just be the pause when going to the menu and not the vSync toggle directly. I need to experiment more, nevertheless, going to the menu and toggling definitely sees an improvement in my case when I re-enable to the sim. Perhaps it allows something to “catchup” during the pause.
There is no build in frame limiter in msfs, it is only possible to enable v-sync on different steps.
With tools like the normal nvidia control panel you can realy limit the fps ( max fps and max background fsp ). But these limiting is not automaticly a sync with your monitor to e.g. avoid tearing. For monitors with adaptive syncs technics it is a bit different, but also then you need to enable v-sync. About an effect on performance I had no idea, should have zero effect.
In addition to MichaMMA’s point about syncing with refresh rate (which I also mentioned), the sim’s internal v-sync setting might allow additional frames to be queued in the GPU command buffer (versus a CPU wait-based limiter). However the GPU command buffer typically only stores additional CPU-prepared frames when GPU-bound. Many people’s performance issues are due to being CPU-bound instead.
may good to link too: in other topics FBW is mentioned as a more likely cause.
Someone mentioned that switching from fullscreen mode to windowed, then resizing the window, also fixed the performance drop in some cases. It sounds similar to what Dizzy described here: