A GTX-1080TI is around 40% higher in benchmark scores than the 1660. I do not want to promise you that you can run the G2 smoothly, Markus. That thing has a lot of pixels.
However: you can see to secure a deal where you can give back the set if it does not work for you. By German laws, in Germany that is automatically the case when ordering in an online shop, and with Amazon i have never had an issue with giving something back if it was no foreign trader than Amazon.
Second, you can see how the set works if you reduce the so-called pixel-density. Even if reducing it to the mionimum it still looks much better than my old Oculus Rioft form 6 years ago. But I run mine at a reduced level, too (without noticing too much difference), so you may not have too much room for further reductions, too.
Theoretically my i7 8700K is slightly faster than your Ryzen, too, but the benchmarks I just saw imply only a
very small gap, you need a magnifier to see them, so I would assume the CPU would not be the problem. Guaranteeing it I cannot. Also, its AMD versus Intel. It must not mean but maybe can make a difference - I just do not know.
Your call. If you can give back a bought VR set, and you are really eager to get it, i would say: get one and see if it works well enough. If not, you can give it back. Treat it well during testing, therefore. If your run into questions and problems, ask, I see if I can help or know the answers.
Good luck!
