Asus Crosshair Hero x570 (Latest Bios as of September 2019)
AMD 3900x
RTX 2080ti
64GB DDr4 Crucial ram 3600 Cl19 ( 1:1 in ryzen master)
Crosair MP600 x 2 - 2tb (4tb total populating both slots)
Same issue as OP - Read and write at max 2.7gbps , Tried fidgetuing with bios , setting PCIE1 + 2 to Gen 4 instead of aauto , tried decoupling . Havent tested corsair Secure wipe utility but will be filing for RMA if not resolved , Im goping to follow this thread and open a support ticket shortly after doing some more benchamrking and accumultaing bios screenshots etc . Ive been a logn term Corsair enthusiast and willing to work on this issue till its resolved , Im sure its just a bit of fidgeting thats required . If anyone has come up with anything please advise