Some of us already have the 3800XT but are not gagged by any AMD NDA, and I am one of those people.
How can that be you ask?
The answer is that I have the 3950X which consists of two upper quality range eight core 3rd Gen Chiplets.
So to find out how high the "new" 3800XT will clock, all I have to do is disable one CCD, and hey presto, instant 3800XT.
Although this is obvious, it seems to have eluded the Tech-Media and so-called "Tech-Tubers", who have shown themselves, even after almost a year, to be incapable of adequately configuring the 3rd Gen Ryzen CPUs - either through laziness or stupidity - even though they get their stuff from AMD for free and I have to pay retail.
Doing the experiment of disabling one CCD on my 3950X I can run my virtual 3800XT at an all-core frequency of 4.5 GHz and run CineBench R20 (so it is a stable clock).
There is however a small problem. With a Ryzen 3rd Gen CPU you cannot set it to more than 4.225 GHz or so (might vary with some motherboards) in the BIOS without Windows 10 being corrupted at boot.
At first I thought it was my motherboard that was having this problem; however in a video JayzTwoCents stated that he couldn't get any of the 3rd Gen Ryzen CPUs to boot into Windows 10 when he set the clockspeed above 4.225 GHz or so in the BIOS.
There is a way around this and to run your shiny new 3800XT to run at 4.5 GHz and I explained my methodology as a step by step guide in the post:
If you try to configure the 3800XT in any other way, then you will be lucky to get 4.05 GHz or so out of it running an all-core load like CineBench R20.