dtparam=pciex1_gen=3
However, we '''DON'T''' recommend you to use <span class="tb_red">WARNING</span> <span class="tb_red">The Raspberry Pi 5 is not certified for Gen 3.0 as it is not officially supported speeds, and connections to PCIe devices at these speeds may not work stablybe unstable.</span>
Then DON'T forgot to reboot