News outlets VideoCardz (opens in new tab) and BenchLife (opens in new tab) have leaked images for various upcoming Z490 motherboards from Gigabyte. More importantly, the evidence suggests that while the motherboards support the PCIe 4.0 interface with Intel chips, the functionality isn't accessible yet.
Intel's original plan (opens in new tab) was to finally bring PCIe 4.0 support on this generation of motherboards. Sadly, the chipmaker ran into some problems with the Comet Lake chipset and just decided to abandon the idea completely.
According to Gigabyte's alleged marketing materials, the company's Z490 motherboards have limited PCIe 4.0 support. The limitation is probably due to the fact that the high-speed PCIe 4.0 lanes are coming from the processor alone since the chipset doesn't provide any. While the Z490 motherboards have the necessary infraestructure for PCIe 4.0, there isn't an Intel processor on the market that can supply the lanes. As a refresher, Comet Lake-S processors are still on the PCIe 3.0 standard, meaning you will have to wait for the next wave of processors, probably Rocket Lake-S (opens in new tab), to get PCIe 4.0.
The biggest issue with the whole chipset fiasco was that many motherboard vendors had already laid out their designs with PCIe 4.0 functionality in mind so it was likely too late to make any last-minute changes. This is why some manufacturers, such as Gigabyte, have motherboards with certain PCIe 4.0 limitations. At the end of the day, the consumer is the one that has to pay the price, literally.
Among the ingredients to get PCIe 4.0 working, manufacturers need to implement a higher number of PCB layers to ensure signal integrity, which explains why Z490 motherboards are thicker than the prior generation of Z390 offerings. Ultimately, the design, along with expensive PCIe re-timers and re-drivers, is likely one of the contributing factors that increase the cost of the motherboard. Early listings show that Z490 motherboards are relatively more expensive (opens in new tab) than their predecessors. Basically, you're paying the PCIe 4.0 tax.
It's uncertain if Gigabyte is the only manufacturer to roll out Z490 motherboards that are geared for PCIe 4.0. We suspect that the several other brands will offer similar designs, although they might not explicitly advertise it. Rest assured that we should only see PCIe 4.0 on Z490 motherboards. The more budget-oriented motherboards, such as B460 or H410 should be safe and might not suffer from significant price hikes.
At any rate, it doesn't seem wise to jump on the Z490 Comet Lake bandwagon. On the motherboard side, you're paying extra for a feature that isn't readily available. On the processor side, you'll need to upgrade to a new processor to enjoy a feature that you already paid for, whether that be in the next six months or a year.