Hello PMDG,

I'd like to report some sort of a problem with the option in the PMDG Setup -> Options -> Performance page in the CDU. It seems certain settings have strange effects on the overall performance of FSX. It was already known reducing the refresh rate to - let's say - 15 FPS, increases the overall framerate of FSX drastically (by around 20%). However, I found that this also has a negative affect on smoothness and causes jumps in framerates sometimes. I'm running VSync 1/2 refresh rate without an FPS limiter, which will run 100% smooth normally, but in the 777 it does not. Only if a put my displays FPS to something higher than 30 Hz I will get the great smoothness but simultaneously causes lower framerates as well. So in other words, I can't run 15 FPS on the displays because I will get choppyness and jumpy framerates, not optimizing the potential of the performance of this plane.

In the NGX this does not happen and for the smoothness it doesn't matter what kind of display refresh rate I'm running, and the same applies for the MD-11. But in the 777 I have to run something above 30 on the displays to eliminate big jumps in framerates. I don't see why this all should be working differently in the 777, perhaps it's a bug but I'm not sure. 

Thanks in advance, hope you guys will look into it.

I run with internal limiter on 30 - 777 displays to 15 works great for me.

 

I have no a idea why this happens. My guess is that when you set displays higher, you actually lose performance and fps drops arround 30, where they should be, and that makes FSX more smooth. Just a guess

I run with internal limiter on 30 - 777 displays to 15 works great for me.

 

I have no a idea why this happens. My guess is that when you set displays higher, you actually lose performance and fps drops arround 30, where they should be, and that makes FSX more smooth. Just a guess

Well then I think the settings sorta interfere with NVIDIA VSync. It works fine when I put them to 60, but to 30 or lower will cause choppyness despite the higher FPS. Works fine with all other planes but not the 777.

 

And the MD-11 FSX wants to take FPS above 60 but VSync keeps it at 30 and no problem either, so don't think it is related to what you suggested. 

This is definitely caused by an intereference between VSync and the panels refresh rate. If I set panels refresh rate to 20 then my FSX FPS counter shows 21 FPS, while I am actually having 30 FPS. So the FPS counter seems to take the FPS from the displays instead of from the entire picture.

If I disable VSync in Inspector than the problem is gone. But I won't fly without VSync.