It has long been the case that Intel offered server chips with more cores than their HEDT chips. Excluding the low end parts based on chips primarily intended for laptops, their current Xeon lineup has dies with 10, 18, and 28 cores, and then they can offer CPUs with intermediate numbers of cores as salvage parts of those dies. For a while, they only offered desktop parts based on the smallest of the dies primarily intended for Xeon. For example, Broadwell-E topped out at 10 cores in the Core i7-6950X.
Then came AMD Threadripper. The Ryzen 7 1800X with 8 cores wasn't a threat to a Broadwell-E with 10 cores for dominance of the high end. But a Threadripper 1950X with 16 cores sure was, even if it had to be a mult-core module with 2 dies. Suddenly AMD had an HEDT part with a lot more cores than Intel offered, and that translated to AMD having the fastest desktop chips in a lot of things that scale well to many cores.
Naturally, Intel found that intolerable, so they pressed their 18-core die into service for the HEDT market. Thus was born the Core i9-7980XE. Of course, if they're going to sell Xeon dies in desktops, they're going to charge Xeon-like prices. While the Core i7-6950X cost $1000 and the Threadripper 1950X also cost $1000, the Core i9-7980XE cost $2000. It is generally a better part than the top end Threadripper, but that $1000 price difference makes it a tough sell for consumers.
But in a sense, both AMD and Intel were keeping their powder dry. AMD offered 32-core CPUs for servers as EPYC, and Intel still had those 28-core Xeons. So why not bring those to desktops? At Computex, they announced that they're doing exactly that.
Yesterday, Intel didn't just show off their new 28-core desktop part. They overclocked it to 5 GHz--on all cores. That doesn't mean that you should expect 5 GHz at stock speed. Beyond whatever amount of cherry-picking they had to do for a demo, the cooling was at minimum a custom water loop, and may have been phase change cooling.
Meanwhile, AMD's Threadripper had basically used the same socket as EPYC, but with two dies missing/disabled/otherwise not functional. So why not just fill in real dies and make them operational as they did with EPYC? That's how Threadripper 2 will top out at 32 cores. AMD says that Threadripper 2 should be available in August.
To put so many cores to good use, you of course need a ton of memory bandwidth. Intel is going to bring their enterprise socket with 6 memory channels to the HEDT market to feed their new 28-core HEDT processors. This isn't just the usual situation of Intel looking at the market and deciding that it needed more CPU sockets; the 28-core Xeons already use a different socket from the 18-core Xeons in order to have more memory channels. AMD is making Threadripper 2 backward compatible to the first generation Threadripper, and still having only four memory channels for so many cores. And while it's backward compatible of sorts, some motherboards likely won't support it, as it's rated at 250 W.
But while AMD's Threadripper and Intel's reaction in Sky Lake X really did push the high-end desktop market forward, the new generation won't do that so much. Quite apart from the prices that you're surely not going to want to pay, the problem is that they're going to be kind of dumb parts. More cores generally means lower clocked cores, and that means worse parts for most desktop uses.
With Threadripper and Sky Lake X, they could just blow out the power budget and keep clock speeds up for solid desktop performance even when you don't need a ton of cores. The max turbo boost was 4.2 GHz on the Core i9-7980XE and 4.0 GHz on the Threadripper 1950X. The 32-core version of Threadripper 2 will reportedly top out at only 3.4 GHz or so. And not withstanding Intel's marketing stunt of an overclock, expect the 28-core CPUs to clock lower than the 18-core ones did.