A blog called ServertheHome has drawn on the latest leaks and info on EPYC Rome to conclude that it could have between 128 and 160 PCIe lanes. By contrast, the competing Intel Xeon Platinum 9200 solution may have only 80. On top of that, the Xeon's lanes may be Gen3, whereas Rome is likely to have Gen4.
https://www.notebookcheck.net/AMD-s-EPYC-Rome-CPUs-could-have-double-the-PCIe-lanes-of-the-corresponding-Intel-chipset.415936.0.html