A better gpu does nothing when you are CPU limited (main thread in the sim fps display). When your main thread frame time is higher than the GPU, it means the GPU is waiting for the CPU to deliver the next frame info for the GPU to render. That’s why I’m sticking with my prior advice. Don’t worry about the GPU right now, because it isn’t your main problem and upgrading it would be a waste in your current configuration.
To maybe put this into perspective in time scales easier to understand, let’s say it takes the CPU 10 seconds to process a frame, but the GPU takes 2 second. That means the CPU sends a single frame of data to the GPU, which then renders the image to display on the screen. Once that image is there, the GPU sits idle for the next 8 seconds while it waits for the next frame from the CPU, with a resulting frame rate of .1 fps. 1 frame per 10 seconds, limited by the CPU.
What you want to do would be like replacing that hypothetical GPU with one that is twice as fast, capable of rendering a frame in one second, thinking this would speed up the fps. If nothing else changes, the CPU still sends a frame every 10 seconds, only the GPU now renders in 1 second and sits idle for 9 seconds. Your resulting frame rate would still be .1 fps limited by the CPU.
If instead you upgrade the CPU and optimize your settings better, let’s say that allows the CPU to send a frame of data every 2 seconds to match the original hypothetical GPU. Now the GPU is kept busy and you’ll see the frame rate jump to 2 fps. Even better if you can improve the CPU to less than 2 fps, because you tend to have less stutters when it’s the CPU waiting on the GPU and thus gives you more headroom for background processes that may interrupt the CPU now and then.
I wouldn’t worry about the RAM just yet. Upgrading it may help some, but I doubt it would be as drastic as others are saying based on my 16 GB running at 2666MHz and don’t have near the high frame times as you. Any benefit you do get from it would be minimal with the CPU being so bound up.
Btw, what is your FSLTL settings at?