As it stands right now, there will be no performance gain in MSFS most likely, unless the 13900k has a higher single core clock speed and more cache than the 13700k. This might change once Asobo switch us over to DirectX12 however, as that allows for better CPU core utilisation, but it likely won’t be a quick improvement, it might take them months or years to fully optimise it for better core usage.
I have a 10 core 20 thread intel i9, and the sim uses 6 threads, five of them lightly, and the main thread is hammered. It’s like having a supermarket with 20 checkout ailses, but 15 are closed, 4 are for people using baskets only, with the one remaining ailse doing all the trolley shopping.
In this analogy, it would be ridiculous to try and cut customer queue times by building a bigger supermarket with 40 ailses, that can scan items 10 percent faster, and then keep 35 of them closed and just get a 10 percent scanning speed improvement on the remaining ailses.
Obviously what you;d want to do is just open more the existing 20 ailses, as if they were all open there would be no queues.
That’s the problem with MSFS, especially using DirectX11.
A 13900k will definitely be a better processor than a 13700k, but right now it won’t make any difference whatseover. At least with the update to DirectX12 coming in August, we will have a few months to see if they can improve the core utilisation and we can all make decisions then.
In my case, I wouldn’t need to upgrade at all if they could use my current CPU fully, but when I open task manager during flight, its only at 20 percent usage which is incredibly inefficient.