ssd wd slot

Hi, I have a WD black SN850 500GB in my M. dewaarena slot login 2_1 slot on my ASUS ROG Strix x570i mobo The only thing I can find in bios is set to M 2_1 link = Gen 4 Yet the SSD is still running at Gen 3 according Dashboard (Capability: Gen 4, Connection: Gen 3) I have the latest non-beta bios (ver 3603) Is there something I’m missing to enable Gen 4 My crystal diskmark is 3770MB/s, so it’s half its