CPU seems to be more important in 3.0 than GPU, my CPU is at 60% (20% more than 2.6) and my GPU is at 6-20% (much less than 2.6 was) My mate gets 95% CPU on his Overclocked I5. 3.0 is deffo much more heavy on CPU.
I've got a 1080ti but I get bad frame rates in SC because of my 3rd gen old I7 and the netcode and bad cpu optimisation.
I wouldn't buy a GPU just for star citizen as SC is incapable of using powerful GPUs to the max at the moment!