It appears new 500 series chipset motherboards for Intel's next-generation Rocket Lake processors are fast approaching, according to Weixin, a Chinese news outlet. Weixin claim that Intel might be releasing new Z590, B560, and H510 via its board partners before the Rocket Lake launch on January 11. Weixin also believes the Rocket Lake CPU launch will happen sometime in late February or early March. As this is a rumor, take everything with a pinch of salt.
If this is true, then the motherboard release will coincide directly with CES 2021 which also begins on January 11. But we still don't know exactly why Intel is releasing Comet Lake supported motherboards a full month earlier than the CPUs intended release date. Potentially this could be good news if you are building a new Intel system in January and you want to use the new 500 series boards before upgrading to Rocket Lake a few months later. This could also enable the 500 series boards to be updated and for bugs to be addressed. But still, this would-be very niche and it would be highly doubtful lots of people will upgrade to a 500 series board before the CPUs launch. Not to mention, Intel's 400 chipset boards like Z490 should be forwards compatible with Rocket Lake including having PCI-E 4.0 support which Rocket Lake CPUs will start supporting.
We can get an idea of what these new 500 series boards will support via our what we know about Intel's upcoming Rocket Lake CPUs. The new chips will be supporting PCI-E Gen 4 out of the box, AVX-512 support, Thunderbolt 4, and more PCI-E lanes, specifically four more lanes dedicated to a single M.2 NVMe slot for storage, just like AMD's Ryzen processors; and an upgrade in bandwidth for processor to chipset communication, from four lanes to eight lanes. Plus updated ports like HDMI 2.0b and USB 3.2 Gen 2.2 (20G). So Intel's new 500 series boards will have to support all these features out of the box.
Besides these, we still don't know exactly what features H510, B560, and Z590 themselves will offer over existing 400 series chipset motherboards, we'll have to wait for that information once Intel talks about these boards next month during CES 2021.
The vast, vast majority of the chipsets / boards will be in OEM systems. A big shift to gen 5 chipsets even if they are running Comet Lake initially, will be a big deal. The OEMs (7 of them) sell abut 17 million PCs per month.
It's the same way they buy a new roof for the building. Based on the numbers on the roof replacement schedule.