CPU core #8 always pegged at 100%

User Support Hub Hardware & Peripherals
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I posted about this over on the r/flightsim subreddit and then I thought it might be wise to post it here too. The community there is toxic and everything gets downvoted. This is basically a cut & paste of what I posted there.

I’ve been monitoring my computer’s telemetry lately while playing MSFS and I noticed core #8 on my i7-9700K is always pegged at 100% while in the sim. The i7-9700K is an 8 core, 8 thread CPU. No hyperthreading.

I took the screenshot of the telemetry just after I had taken off from Salt Lake City and set auto-pilot in a DA40.

I’m not making this post to complain about any game performance issues. In fact, the game has always performed flawlessly, for the most part, for me since day 1 (game purchased 23 AUG).

I wondered if anyone else has noticed this behavior on their CPUs. Does it vary by model/generation and/or brand (Intel/AMD)?

If it’s relevant, my hardware configuration and game settings are below:

My CPU is paired with an EVGA 2060 Super XC Ultra 8 GB and Corsair 32 GB DDR4-2666 CL16. All game data (launcher/UI and packages) is stored and ran on a WD Blue SATA SSD. I have the Steam edition. Windows 10 and MSFS Rolling Cache (16 GB) are on a WD Black SN700 NVMe SSD.

Game settings are Full Screen, 1080p, High-End Preset, V-Sync off, 100 Render Scaling. I changed the following preset settings: Motion Blur off, Lens Correction on, Lens Flare off. Generic Plane Models are off for AI and Multiplayer.

I average 55-60 FPS. I see it as low as 35-40 at certain locations and as high as 70-75 in others.

GPU Temp averages 60-62 C. CPU Temp averages 51-53 C.

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I used to watch my cores and wonder what was actually happening too. I do set affinity off on my Core 0
for flightsim.exe so windows has some working space. I believe it has helped but not sure as when I started doing that was after 2nd update, but I will say I have had no more CTD’s at any time aside from drone camera usage(fixed now I think) and flight plan manipulation in game (fixed now I think).
My specs are very similar to yours
I9 9900k
32 GB Ram
2060 Super

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What you’re seeing is the nature of the beast:
A simulator like this will always have a ‘main thread’, that keeps all the tasks running on the other threads in sync. This main thread can only run on a single thread (or in your case, since you’re not using HT, a single core).

There will be small optimizations in the future, moving more workloads away from the main thread, towards other threads, but those new threads will need to be kept in sync as well, so it will still have a load on the main thread.

Most games (and complex simulators especially) all have this characteristic. More productivity focused software (like tile based renderers) will be able to utilize all the cores/threads more effectively, since in software like that it doesn’t matter that 1 task is done earlier than the others. In a simulator this simply can’t be done.

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