Which should I go for to run MSFS in 4k?

The CPU they will run with is AMD 5800x3D and 32G of RAM. 
 

I currently run Radeon 6800xt and find that I am always GPU limited. I usually run PMDG 737 and FBW Airbus. 
I think I am quite modest with settings as I run LOD 70, and rest is medium, with clouds set to high. No AI traffic, low trees, low waves, etc  

It grinds to stutterfest even without Vatsim traffic, while with Vatsim it is barely acceptable.  
 

Thank you for all advise. 

There's no argument the 4080S is a 4k card, the 4070 and all its subvariants are the ideal card for 2K. Though it might bear taking note as to whats causing you're stutters. In MSFS's own situation, being GPU limited is a good thing.  I would open the fps display in MSFS and take note of your VRAM usage (Not Task Manager VRAM usage), or if you can post of picture of it here while you're dealing with a stutterfest.

It's possible that buying another GPU won't help you here. Can't know until we see the FPS display though

Here are the screenshots of the FPS display from within MSFS.

 

On 7/29/2024 at 3:12 PM, Lucky38i said:

the 4070 and all its subvariants are the ideal card for 2K.

I see this often and it is not true. The 4070Ti Super is easily a more ideal graphics card for MSFS in 4K. With graphics on Ultra, and typical sim usage, the limiting factor with a Core i7 14700K running stock clocks and a 4070Ti Super is always the CPU. So why get an even more powerful GPU when the fastest CPU’s money can buy right now can’t keep up because of the way MSFS relies on the CPU. Save the difference to buy the fastest CPU you can for a far more balanced and better performing MSFS system.