Ever since Coffee Lake appeared on various leaked Intel roadmaps, there have been questions about whether it would be supported on existing 200-series motherboards. Back when Intel used a Tick-Tock model, there was less uncertainty–LGA 1155 supported Sandy Bridge and Ivy Bridge, Z87 supported Haswell and Devil’s Canyon (Z97 supported Broadwell as well), and the 100 & 200 Series both support Skylake and Kaby Lake.
Intel’s new PAO (Process – Architecture – Optimization) process made it plausible that the company would continue to support newer chips on older platforms, but a tweet from Asrock made it clear that’s not what is happening, as shown below:
This is the kind of information Intel typically sits on until it’s ready to reveal the entire platform. We know that Coffee Lake is built on Intel’s third-generation of 14nm technology and that Intel expects 14nm++ to provide better benefits for these market segments than its own first generation of 10nm, as described in the slideshow below:
Coffee Lake’s major draw, besides being based on a tweaked variant of Intel’s 14nm, is that it supposedly will add more cores to Intel’s existing Core i7 lineup. This hasn’t been confirmed by Intel, but leaked documents (salt, grain, etc.) have predicted a Core i5 part with six cores and no Hyper-Threading, and a Core i7 with six cores, 12 threads, dual memory channels, and standard Core i7 branding.
Supposedly the Core i7-8700K will have a base clock of 3.7GHz, a single-core maximum of 4.7GHz, dual-core max of 4.6GHz, quad-core at 4.4GHz, and an all-core maximum frequency of 4.3GHz. While they still use LGA1151, however, apparently they require new motherboards and chipsets to drive them. Pushing six-core chips into the mainstream may not have been confirmed, but it’s a smart move for Intel to make. AMD’s Ryzen 5 1600X is a 6-core/12-thread behemoth at its $ 249 price point, so bringing six core chips out of the HEDT market and into upper-mainstream configurations only makes sense.
As for why Intel needs to release new chipsets, the explanations range from the technical (different pin layouts to deliver power and connect the cores to DRAM) to the market-based (Intel could be releasing new chipsets because it can). Both are more-or-less equally plausible at this point; Intel has a long history of releasing chipsets far more often than AMD, and its users have an equally long history of complaining about it, then buying Intel anyway. It’s a song and dance the company is entirely used to, and we likely have Ryzen to thank for Intel’s sudden rediscovery of the fact that desktop CPUs can have more than four physical cores. It’s certainly no coincidence that Pentiums got Hyper-Threading, Intel launched its entire X-Series, and Coffee Lake leaks predict six-core mainstream desktops in the same year that AMD launched its first competitive CPU in six years.