The official AMD site does not provide exact specs for the new Pro 500 chipsets, but it looks like Lenovo already plans to release some IdeaCentre ThinkCentre models that integrate a Pro 560 chipset. According to the Lenovo spec sheet, the Pro 560 chipset appears to support up to 32 GB DDR4-2666 RAM and is only compatible with the PCIe 3.0 standard.
https://www.notebookcheck.net/AMD-extends-mini-PC-support-with-new-AM4-Pro-500-series-chipset-for-budget-builds.452354.0.html