For those who were hoping to see PCI-Express 4.0 on upcoming Intel 400-series motherboards it looks like it is not happening. According to Tom’s Hardware they spoke to multiple sources at CES 2020 and apparently Intel encountered problems implementing PCI-Express 4.0 with the Comet Lake chipset, so Intel 400-series motherboards will only support PCI-Express 3.0 signaling rates when they come to market.
It was expected that 400-series chipset motherboards would come with support for PCI-Express 4.0, so even if upcoming Comet Lake desktop processors lacked gen 4.0 root complexes, the boards would be fully ready for the new bus standard with 11th gen Rocket Lake processors. Many 400-series motherboards are in their final stages of development and some will come with PCI-Express 4.0 enabling components in the hope that Intel will allow Gen4 with Rocket Lake processors, but it is also possible that vendors could cut Gen4 support entirely to cut costs.
It is also being reported that Intel has delayed the launch of their 10th generation Core desktop processors and 400-series chipset to Q2-2020. This makes sense as we did not see a single 400-series motherboard at CES 2020.