Starting off with what is likely the most obvious conclusion - the AMD Threadripper 3rd Gen CPUs are really, really good for Premiere Pro. The only real caveat is that they are only better than the new Intel X-series CPUs when it comes to exporting. For live playback, all of the Threadripper 3rd Gen and Intel X-1000 series processors (with the exception of the Core i9 10900X) performed about the same on average. There are a ton of nuances with individual CPUs being better for specific codecs (or even the same codec but at different framerates), but overall you can consider the Threadripper 3rd Gen and Intel X-10000 series as being equal for live playback.
This isn't all that exciting from an AMD vs Intel perspective, but it is worth noting that both the new Intel and AMD processors saw a pretty decent gain in performance over the previous generation. While the Intel X-10000 series is only about 7% faster than the X-9000 series models for live playback, the AMD Threadripper 3rd Gen is about 20% faster than the previous generation Threadripper 2970WX/2990WX.
Like we mentioned earlier, exporting is where things get interesting. Here, the AMD Threadripper 3960X and 3970X are a huge 35-40% faster than the Core i9 10980XE! It is worth repeating that with the X-series price drop, this isn't a perfect 1:1 comparison since the 10980XE has an MSRP of $979 while the 3960X and 3970X which have an MSRP of $1,399 and $1,999, but it is comparing the top model from both Intel and AMD which in and of itself is a completely reasonable comparison to make.
Even factoring in the MSRP, however, Intel only barely comes ahead - and even that is completely subjective on what is most important to you. Compared to the AMD Ryzen 9 3950X, the Core i9 10940X is about $35 more expensive, but about 3% slower overall. On the plus side, the 10940X is 7% faster for live playback (which most users value higher than export performance), supports 256GB of RAM, has more PCIE lanes, and has the option for Thunderbolt on supported motherboards. It comes up often, so it is worth repeating that no AMD platform has a certified Thunderbolt solution at this time - ASRock has a few Ryzen boards that have un-certified implementations, but trust us, you definitely don't want to risk it when it comes to something as finicky as Thunderbolt is on PC.