Faster memory does not necessarily yield better performance in this game. The 3080 may pull ahead in 4k but more vram and a faster CPU are the most important things for a smooth running sim. Extra ram as well.
If you think faster vram is more important then try bumping your settings all the way up on your 3080 at a higher resolution. It is going to stutter like crazy.Neither the 3080 or 3080ti does well in DX12. What happens when the games supports more features like RT? You’ll need more vram. Look at the 4080. That monster has 16gb vram. Maybe Nvidia is learning from Amd after all