LINKUP PCIE 5.0 Riser Cable | for Vertical GPU Mount | ITX Double Reverse | Graphics Card GPU Ready | Usable with PCIe 4.0 & RX 9070/ RTX5090 | 21cm (Total Length: 23.2cm)

a 5080 is a pcie gen 5 gpu, but b550 only supports up to gen 4. you can get a gen 5 riser cable for future proofing but they are pretty expensive. because your motherboard only supports gen 4, you will want to go into your bios and set pcie link speed to gen 4, otherwise you may run into display issues most sandwich cases use a ~20cm double reverse riser cable- think of "double reverse" as both ends of the cable have 180 degree terminations. you can get a 21cm if you want some extra slack to be safe. linkup is my preferred brand, like this one https://a.co/d/0hGOlJaN you should also try to ensure your bios is up to date, as this can help improve compatibility with risers which can be noticeably unreliable