Ironically, high end cards usually only have small penalties for having a previous gen PCIe. On a full x16 lanes, there’s usually bandwidth to spare. Although you wouldn’t want to put a RTX 5090 on PCIe 3.0. It was the RX 6500 XT with its mere x4 lane count that took a significant hit running on PCIe 3.0 instead of 4.0. That was not a good limitation for that market segment since the low end is where people are most likely to try to avoid upgrading motherboards/cpus.
Ironically, high end cards usually only have small penalties for having a previous gen PCIe. On a full x16 lanes, there’s usually bandwidth to spare. Although you wouldn’t want to put a RTX 5090 on PCIe 3.0. It was the RX 6500 XT with its mere x4 lane count that took a significant hit running on PCIe 3.0 instead of 4.0. That was not a good limitation for that market segment since the low end is where people are most likely to try to avoid upgrading motherboards/cpus.