In its present implementation, socket AM4 motherboards have a complete of 24 PCI-Specific gen 3.0 lanes from the AM4 SoC, apart from 6-8 gen 2.0 lanes from the chipset. From this SoC price range, 16 lanes are allotted for PEG (PCI-Specific Graphics), 4 lanes as chipset-bus (connecting the SoC with the chipset), and the remaining 4 lanes powering one 32 Gbps M.2 slot. Extra M.2 slots are both gen 2.0, from the chipset's downstream lane price range, or break up from the PEG price range. The Z490 overcomes this with a downstream PCIe root advanced that is not simply 50% broader, but additionally twice as quick, with PCI-Specific gen 3.0. The remainder of its feature-set seems to be equivalent to the X470. There is no timeline on after we can anticipate Z490 to launch.
Source : TechPowerUp