Total overkill. 8 core cpus (16 threads) should be more than enough for the next 3-4 years for gaming. Single core performance (highest ipc) still is king and will be for the next years. Next gen consoles will have 16threads (one for 3d audio and one reserved for os, so 14 threads max. effectively for the game). So this will be the majority of hardware base software are optimized for. Rarely game benefit from more threads available.
Therefore intel 10700kf (k vor overclocking and f without graphics) for 350€ is imho a good choice if you want to buy now or want to buy intel. Makes 5.10ghz stock and should easily do 5.2ghz on all cores with good cooling (AIO maybe?) but consumes over 200watt peak then alone.
With the 3090 demanding measured over 400watts at 2100mhz an 850watt psu should be fine.
Better wait for the zen3 (Ryzen 4000) cpus being announced on beginning of Oktober. Ipc is said to increase 15% over Ryzen 3000 series which brings it at least on par with intel 10gen ipc. And the clock is supposed to increase a few 100mhz over the ryzen 3000 series, too. The 3800xt is the one with the highest boost clock nowadays (4.7ghz) and comes with a cooler which should cool even all cores at said 4.7-4.8ghz.
So right now intel ipc is still best for gaiming. But for vr on 8kX the resolution is so high that you are very rarely in an cpu limited scenario.
Gigabyte Aorus Elite or similar 180€ - 200€
Ryzen 3800xt 350€
DDR4 3600 Ram g.skill ripjaws cas 16/19 32gb kit 135€ - 150€
Corsair mp600 1tb pci-e gen 4 ssd nvme tlc nand 190€ -200€
Gigabyte Aoruns Elite z490 190€ - 200€
Just the basics…
3090 is imho a total rip-off by nvidia. But very likely the fastest card for the next years.
I am thinking about going 3080 this time (still min. 30% faster than my 2080ti) for half the money.
And if rdna 2 big navi from amd is really good (we will know after Oktober 28), maybe i buy later a faster card if i want more performance. I just don‘t want to support nvidias pricing policy…