The Threadripper 1900X doesn't go nuts with core and thread counts—it has 8 cores and 16 threads, versus the 12C/24T Threadripper 1920X ($800) and 16C/32T Threadripper 1950X ($1,000). That is the same core and thread count as AMD's Ryzen 7 1800X, but at nearly double the TDP (180W versus 95W).
You get a slightly faster base clock on the Threadripper 1900X at 3.8GHz versus 3.6GHz on the Ryzen 7 1800X, and a 100MHz higher extended frequency range (XFR) at 4.2GHz versus 4.1GHz. Both CPUs have a 4.0GHz boost clock.
This begs the question, why go with a Threadripper 1900X when the Ryzen 7 1800X is nearly as fast, has the same core count, and consumes less power? The answer lies in architectural and platform differences.
The Threadripper 1900X is a more affordable gateway to AMD's X399 platform. Where the Ryzen 7 1800X supports dual-channel memory and offers 16 PCIe lanes for high-speed components, the Threadripper 1900X supports quad-channel memory while serving up a whopping 64 PCIe lanes. And later this month, AMD says it will update its X399 chipset to support booting from NVMe drives configured in RAID.
One other thing to note is that AMD said its Threadripper CPUs are plucked from the top 5 percent of its die. In theory, that should mean better overclocking headroom versus Ryzen 7, though we have not seen anything dramatic so far in our own testing.
None of this means you should rush out and buy a Threadripper 1900X. Whether it's right for you depends on what you need your system to do. For strictly gaming, a less expensive Ryzen 7 or Intel Kaby Lake processor will deliver more noticeable bang for your buck. But for certain productivity chores, like POVRay and Handbrake, it's not a bad idea to consider a Threadripper CPU.
AMD also makes the case for professional video streaming from a single system, rather than having a dedicated streaming PC. Having those additional PCIe lanes and quad-channel memory support helps ease the strain. In one example, AMD showed a setup with a graphics card, streaming card, and NVMe RAID configuration running at the same time and taking up 48 of Threadripper's 64 PCIe lanes.
One thing to keep in mind is that existing X399 motherboards are not exactly cheap. A quick glance on Newegg shows just six options ranging in price from $340 to $550.