Thank you for your kind support. I will use it as a reference when purchasing.

Going 3x 50" at the moment, building my aluminum mounts. 
 
3090 is the way to go now at the moment. Personal opinion, even 3090 is not  enough. I am talking about pure 4K not DLSS or FSR.
You need to check benchmarks for 8K resolution. Which GPU gives more FPS at 8k (3090 in this case) is your GPU.   (# of pixel 8K >  # pixels 3x 4K)
 
You need more than 20 GB of VRAM and aim for at least 20-30fps. (forget about 60fps impossible with full graphics).  So i believe when MS/Asobo release Xbox version and DX12 version,  we may do it with nvidia 5000 series in the future :D .
 
For screens just in case you need and planning to go Big screen -> GO 43 inch IPS TV if  PC monitor + Scenery is important (good ones are expensive), VA panel if you go high quality. In short  Sony x85j > TCL 43 inch VA tv for flight sim kind scenery games and for your eyes. Money is not a problem?   LG Oled. no need to think about it.

24G memory is necessary for flight simulator. so go for 3090
 

tanagon
After all I wanted 3090.But I can see that 3080ti is also high enough

I'd argue if you're okay with a 3080ti, then you're probably okay with a 3080 (if you can find one). 

I would like to buy 3080ti or 3090 with such a price difference

VRAM is prepared for future games, isn't it?

tanagon
I want an explanation of Texture Fill Rate

Texture rate,  refers to the number of textured pixels that a graphics card can render on the screen every second. This means that it refers to the speed at which a graphics card can essentially “fill” the screen with pixels.

Thank you very much. I understand.Does it affect the frame rate?

tanagon
I can buy thousandof 3090

Wut? You started a thread asking what GPU you needed and left saying "tis but a pittance".