Like many other friends who have a decent computer but continuously haunted by the “Limited by MainThread “ in RED phenomenon while displaying the FPS under Developer Mode, I tried somethings last weekend that turned it in GREEN, even with about 10 fps increase in average.  The result really exceeds my expectation.

My computer is still the i9-11900K CPU with GeForce RTX 3080Ti card and 34-inch (3440 x 1440) Mi monitor.  Here’s what I did:

1. nVidia Settings

The driver is 546.29 which was released earlier this month.  Major changes were done in the Global Settings, which are highlighted in yellow.
For the DSR – Factors and DSR – Smoothness, frankly I am not quite sure about the effects of them. I just tried them on to see if they would bring any positive result.  And the overall impression seems to be better with them enabled as indicated.

Lowering DSR – Smoothness improves sharpness.  At the moment, I prefer smoothness.  So I set it to 100%.  It doesn’t mean that it couldn’t be changed.

The Max Frame Rate could also be a smaller number.

Edit: A newer nVidia driver 546.33 was released yesterday (December-12).  It’s been tested and confirmed getting the same result.

2. MSFS Graphics Settings

All my changes were based on the default Ultra Global Rendering Quality profile.  The alterations were chosen to reduce CPU loadings for smoother performance as I don’t see significant differences from lowering the specs.  I might further push them in the future.And in this fix, the most critical step that turns the “Limited by MainThread” issue from RED to GREEN is by increasing the FRAME RATE LIMIT from 30% MONITOR REFRESH RATE to 50% or 100% after all the other changes.

I chose to use 50% MONITOR REFRESH RATE in the end as the overall performance of MSFS is the most stable with the 50% setting under various scenerios.

If you, like me, are bewildered by the “Limited by MainThread” in RED paradox, hope above helps or give you some hints.

Note that my monitor’s Refresh Rate is 144hz.   Your mileage may vary.
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