Microstutters, Complex Aircraft, and Panel Updates

[dsymanow]

To make a long story short, if you're flying complex aircraft with complicated instrument panel pop-ups, and you're having microstutter problems, try adding the PANEL_MAX_UPDATE_PER_FRAME option to your config file (per the LM learning center text).

I have a pretty high end system, and I fly aircraft with complicated systems and panel models (e.g., the MILVIZ F-4 and the PMDG 777ER), and I've had chronic problems with microstutters. I had some free time this holiday season, so I did a deep-dive on the problem, and this is what I learned:

1. On some aircraft, activating a pop-up panel (e.g., GPS) on the runway prior to a flight induced significant microstutters for that flight, even if the pop-up was no longer displayed.

2. Not activating the pop-up resulted in no stutters.

3. Adding PANEL_MAX_UPDATE_PER_FRAME fixed the issue - no microstutters regardless of pop-up use.

I suspect that many of the pop-ups remain active in the background regardless of whether they're displayed. If the pop-up software doesn't explicitly link its timing to frame rates (i.e., update no more than once per frame), and the code takes significant processor cycles to execute, then it can cause microstutters. GPS, or anything that displays complicated images (e.g., maps), is probably more sensitive because that activity then influences the actions of the single CPU core that renders images in P3D.

This would also explain why microstuttering is sometimes hard to replicate - it depends on the past history of pop-ups.

YMMV

[johnfairm]

Hi Dysmanow
I would be interested in trying this as I too have a problem with micro stutters.
Which section of the config file should it be placed in?
Many thanks
Best regards
John

[chann856]

From the Learning Centre (copied below).

Thank you, great tip and it has worked for me.

Still get Vsync stutters but that is another issue.

[PANELS]
PANEL_MAX_UPDATE_PER_FRAME = 1
Non-Default entry. This entry will not exist in your Prepar3D.cfg file by default and must be added to the file.

Performance Tuning Tip:

If 1, panels update no more than once a frame even if FPS drops below 18. This should not change the end result displayed unless update scripts rely on the 18hz timing to do stepwise simulation in a gauge script.

If 0 (default), update will get called more than once per frame if application framerate is lower than 18.

[dsymanow]

John -

It goes in the file Prepar3d.cfg in the [PANELS] section:

[PANELS]
PANEL_MAX_UPDATE_PER_FRAME = 1

[johnfairm]

Thanks very much. I'll give it a try.
Many thanks
John