My PC is an ASUS ROG Maximus XIII Extreme, i7 11700k CPU, 32GB DDR4, RTX380 GPU, 10GB.

I have been trying to get the best possible placement of the image displayed on the Monitors to the left and right of the central monitor. I did not do a perfect, but a tolerable positioning, so that in sum I had the benefit of the immersion effect, and this with tolerable FPS between 30 and 35 FPS. Now, recently, I experimented with spanning the single windowed view over those 3 monitors. While loading MSFS 2024, the video stream saw the benefit of pursuing this single window approach. Impressive! But then a message popped up reporting insufficient GPU memory, and the FPS dropped to 5 FPS making it impossible to run MSFS 2024 in a single window form, and I had to switch back using the functionality to add 2 windows, so that the display is shown covering those 3 windows.

 

So my question is, why the FPS rate is about 35 running MSFS 2024 in the 3 windows mode, but only about 5 FPS in a single window mode spanning the same 3 monitors, each 3840x2160.

My thinking about it gets to the result that running the 3 window mode the frame generation is done with a single execution pipe for each window, while running it with just one window the rendering is done in just a single pipe. That would mean that MSFS 2024 is running with a single window just in one pipe, while with the 3 windows, each window is served by its own pipe, benefiting from a resulting parallelism.

If this assumption were correct, then MSFS 2024 would require implementing the same parallelism used with two added windows when running in just a single window mode to achieve the same parallelism and FPS performance as with running 3 windows.

As the resolution and size of monitors keep growing than such a parallelism would also be required.

I have started a cue that reflects my economic limits. I am just now upgrading the DDR4 memory from 32GB to 64GB. The next step would be in 1Q26, when hopefully an RTX 5080 GPU with at least 20GB of DDR7 would drop to 1k or less Euros. An upgrade of my motherboard, CPU, and power supply

to address the CPU bottleneck would have to wait until 2H26 at least.

What just came into my mind, what about installing i.e. a second RTX 3080 PGU on my motherboard and connecting one of the 3 monitors to that GPU?