It's hard to cool 307W over extended periods without your computer becoming really loud, even with a water cooling setup.
Now, if they had that kind of cooling available, they could have easily gotten a lot more performance out of the Ryzen, while the i9 is already operating at the limits of what consumer grade cooling can sustain.
There's no way that Intel processor is beating a 5950X that is also drawing 300W. At that point some Ryzen's will be operating at close to 6GHz per core.
The most interesting takeaway is that Intel apparently has no qualms selling a processor with a stock configuration that draws 300W.
Also their Ryzen numbers are beyond suspicious. On a silent configuration (peak power draw ~209W, 175W sustained, some undervolting) my Ryzen 5900X hits a Cinebench R20 score of 8835 vs their 8390. I suspect my rig is worse since I cheaped out on the RAM, but I wouldn't know because they omit information about the Ryzen test rig.
Their Ryzen numbers don't add up with other benchmarks around the internet either: The 5950X should hit around 10400, and the 5900X should hit 8600 in their stock configurations with mid-to-high-grade RAM[1]. Their scores are 400 points and 200 points lower respectively.
To get numbers as bad as theirs, I have to mismatch my FCLK and RAM intentionally. But again, we don't know what their setup is because they didn't tell us.
We however do know that they used DDR5 RAM for the Intel processor, which the current gen Ryzen don't support. Likely some performance was gained there as well, but obviously they didn't test the Intel processor with DDR4 RAM to get an idea of how much comes down to faster RAM. It's still fair to use DDR5, since the Intel processor supports it, but it's hard to say much about the Intel processor performance (development) itself without some additional information. Without this information we don't know whether we can expect the next generation of Ryzen processors with DDR5 support to immediately leave Intel in the dust again, or whether DDR4/DDR5 doesn't really matter.
[1]: https://www.guru3d.com/articles_pages/amd_ryzen_9_5900x_and_...