Limited by Main Thread? New build I9-13900

Hi All,

I have just completed a new build:

I9-13900
64GB DDR5 Ram
1080ti from previous build (waiting to upgrade later this year)

In MSFS, the Sim is still telling me I am limited by Main Thread, when I was expecting to be limited by GPU?
On the ground at EGLL with the Fenix, I was getting about 30 FPS with Vatsim FTL enabled (it was quiet) which isn’t bad considering.
However in the climb/cruise, it was only mid 30 FPS?

Based off Q8 Pilots MSFS settings video, I set Terrain LOD to 110 and Objects LOD to 150?

Is this an issue with MSFS at the moment, I just updated to the latest Nvidia Driver before this flight too.

seems is info enough :sweat_smile:

There are still situations where also the singlecore performance from an i9 comes onto its limits.

Open Taskmanager… check that mainly the P-cores are used ( the first 16 ) and more each 1…3…5… core ( the real cores ) , and all is fine. In usually situaions your 1080Ti should limit the fps, depends on resolution you play. Then close the DevMode and enjoy MSFS…

I’m guessing you’re using 1080p, even a 1080ti will struggle to be gpu limited. Make sure you start with graphics ultra and adjust downwards to find your sweet spot (e.g. clouds down to high gives a decent fps boost)

I have seen streamer use the Fenix though and receive 50FPS at EGLL with FTL online, of course they have a 4090 though…

I have checked the P Cores, 1,3 and 5 are showing as parked amongst other cores too?

Could you elaborate? I got mine to be GPU limited pretty easily on 4k ultra.

1440P which doesn’t help I know.
I have turned down the clouds to High but no noticeable FPS boost in dev mode.

Any boost only really happens if you are actually gpu limited. I know the Fenix is hard on the cpu so maybe easing traffic settings might help.

therefore I allways check the taskmanager ( or similar tools ) to see the load on the components. I not really use the DevMode.

Can you made a screenshot of Taskmanager ( with CPU and GPU ) ?

I was in same situation , just with a 2080TI. And because of my 2080TI I got not higher fps than before, because in 4K the 2080TI just run at 100%. But all that little stutters some times are gone and the fps range which former was like 20 - 40 ( also my vsync max limit ) was gone too. In nearly each situations the i9 was able to hold the GPU at 100% ( not tried with a Fenix ).

MSFS used mainly the Main-P-Cores, rare the HT-Cores and as expected not realy the E-Cores.

PS: because defect mainboard, I’am still waiting for replacement, so can’t do additonal tests with that CPU at the moment

Even all traffic settings are at zero.
Is it due to the GPU anyway, because the CPU is the latest you can buy so surely even at medium settings you wouldn’t be CPU limited?

Any other ideas? or is it just the fact the Fenix still isn’t really optimized?
But again, i’m surprised I haven’t seen GPU limited once during the flight?

Even lowering both LOD to 100 makes no difference?

I think you need to update all your mainboard drivers etc. and possibly adjust your bios settings (e.g. turn off virtualization) but I can’t help much more as I’m AMD. Set DX12 (+ clear rolling cache) and in task manager right click on the cpu graph selecting logical core view, if you are mainthread limited then at least a couple of cores should be working hard and if not you need to investigate why.


Have you played around with these settings? Did make quite some changes for me.

For benchmark purposes, you can try load in a 152 and see what that does.

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I currently have the Display to Quality but will try setting it to Performance at end of the flight upon return to EGLL.

I have just enabled V-SYNC with a locked refresh rate of 50hz and that made it go to GPU limited but locked the FPS at 25FPS.

Bios and drivers are up to date, but will try turning off virtualization (if enabled). I can see cores working hard.

I suggest “render displays on:” GPU and turn off any frame caps, v-sync etc. you need to get that graphics card working hard… PS. I find Mainthread limited below 1000ft and gpu limited above to be optimal however I only fly gliders, it may be different for liners.

Try both DX11 and DX12 to see which is best