Several Gigabyte Intel Z490 motherboards with PCIe 4.0 support have been found.

Let's start with what we know. There seems little reason to believe that Intel's Comet Lake processors, which will reportedly be announced a week from tomorrow, will support PCIe 4.0. The distinction between chipsets, CPUs, and motherboards that support PCIe 4.0 is going to be very confusing.

According to marketing materials obtained by VideoCardz, Gigabyte's Z490 lineup (LGA 1200 compatible motherboards) for Intel's 10th generation processors has a limited number of PCIe lanes with the necessary PCIe 4.0 bandwidth repeaters; two PCIe slots and one M.2 SSD slot are reported to support PCIe 4.0.

This feature is limited, and Gigabyte's motherboard leaker renders the PCIe 4.0-enabled slots as "reserved for future" (good point, Komachi).

This suggests that Intel Comet Lake processors will not support PCIe 4.0 anytime soon. In fact, it seems likely that this feature will remain intact until Intel's (next) next generation CPU family: Intel Rocket Lake. [Both Intel Comet Lake and Intel Rocket Lake use the LGA 1200 socket, with vague promises of backward compatibility with the Z490 and both generations of LGA 1200 processors. This could explain Gigabyte's enthusiastic support for PCIe 4.0, as leaked specs suggest that Intel Rocket Lake will support PCIe 4.0 from the CPU.

Stay with us so far.

It's PCIe 4.0 lanes from the CPU, not the chipset; Tom's Hardware reports that Intel had trouble implementing PCIe 4.0 support from the chipset and had to leave it at PCIe 3.0. However, they have reportedly succeeded in integrating PCIe 4.0 into the CPU itself.

This is because Gigabyte can only tentatively offer PCIe 4.0 slots for bandwidth via the 20 PCIe lanes supplied directly from the CPU, not the remaining 24 lanes supplied by the chipset.

In summary, PCIe 4.0 support for Comet Lake is still unlikely, Rocket Lake may have PCIe 4.0 compatibility in some slots, and the Z490 platform will remain compatible with Comet Lake and Rocket Lake processors will likely be compatible with Comet Lake and Rocket Lake processors. We should add that none of this is new information, but it adds a bit of legitimacy to a shaky and lengthy situation.

But why anyone would buy a Comet Lake chip compatible with a Z490 motherboard later this year and then upgrade to a Rocket Lake chip 12 months later for the purpose of unlocking the motherboard's PCIe 4.0 capabilities is beyond me. [PCIe 4.0 has enabled faster NVMe controllers and SSDs, but what benefit does that have in the game? Aside from the benefits it brings, some RDNA graphics cards offer nominal support. [Currently, PCIe 4.0 is only available on compatible X570 motherboards, but mainstream B550 motherboards will also support PCIe 4.0 in June.