6GK7543-1MX00-0XE0 TIM 1531 IRC SIMATIC S7-1500 ...
***Slot 5 provides the width of PCIe Gen4 x16 when Slot 4 is not in use, and provides the width of PCIe Gen4 x8 when Slot 4 is in use. Card dimensions for PCIe ...
Everything You Need to Know About PCIe 4.0 - trentonsystems.com
The PCIe standard is backward compatible, so an older PCIe card operating on PCIe 2.0 standard will fit in a PCIe 3.0 slot.
