This is a double update: one CPU, one GPU.
Let us begin with the section that contains (on balance) good news for PC builders!
The Good and the Bad of the RTX 4070
The RTX 4070 launched recently, with a $600 price tag. Its performance is practically identical to the RTX 3080 ($700), but this card has much lower power draw, and thus lower operating temperature and noise. For anyone who has $600 to spare, this is a good option.
Unfortunately, nVidia (along with everyone else, it seems) has gone bonkers with pricing. $600 is not cheap. Flagship top-tier cards used to cost $500-$600, with the just-two-generations-ago RTX 2080 launching for $700. The 4070 is not a flagship card. There is the 4090, 4080, and 4070 Ti before it. And no! No! No one can use the pandemic as an excuse for these excessive prices!
The Excellent and the Terrible of the Ryzen 7 7800X3D
The R7 7800X3D is a very similar CPU to the R9 7950X3D before it, so you can read all about that. This CPU also has huge amounts of “3D” extra cache, so for applications that can utilize that cache, this CPU is fantastic. The CPU is very power efficient, and it is available for $500, so it is cheaper than the $700 7950X3D.
Unlike the 7950X3D, however, the 7800X3D has a serious problem: In normal applications, its performance is severely handicapped, to the point that it is inferior to the 7700X. Yes, the shiny new $500 7800X3D is inferior to the $350 7700X, and that is just not acceptable. With such a huge performance loss in non-gaming stuff, why not just buy a cheaper CPU and use the saved $$$ to buy a better GPU for games?
The Update
We will be adding the RTX 4070 to the Excellent and Outstanding tiers of our main build chart, but not adding the 7800X3D till it gets a serious price drop.
Sources
(I love the megathread threads!)