NVME and GPU performance problem

At first, I convinced that I have a defect MOBO, and seller doesn?™t want replace it by RMA. AsRock support doesn?™t respond on my questions. Almost every day, this board brings me new surprises...

In this case: I bought RX5700 and problem started. I remind that I had problem with RX Vega on this board, I sold my GTX 1080ti and bought RX5700. After I install new GPU when I tried to power on my pc MOBO not detect any storage devices, but all it connected. After 2-3 hardresets all Sata devices recognize but main NVME M2 not! Sure, I read manual and know that when M2 installed Sata30 port disabled. When I press power on button for shut down PC and waiting 5-7 minutes and power on it again ??system starts and all storage devices works fine BUT... GPU not works at full speed. I have problem with install Adrenaline 2020 drivers, and get error 173 when trying to install it. If I replace M2 NVME to SATA M2, all works properly. No problem with Install Adrenaline 2020. I checked NVME and GPU on another PC, they works perfect. NVME Ssd worked perfect with 1080ti.

Mobo z370 fatality itx/ac
ddr4 2x16gb Corsair LPX 3000MHz
CPU i7 8700k
GPU Sapphire RX5700
NVME m2 Samsung 960 EVO 256gb

Thanks for response, I tried all steps what u describe above. And I can?™t downgrade BIOS from 4.30 to 3.40. But thx for advice, if I did it i get brick board. Because you know.. Intel ME. I glad to see that all works fine in your lab. I?™ts not answer, I mean If I bought macbook pro with defective battery Apple doesn?™t tell me that all fine because in their lab laptop have not this problem. Apple will solve my situation, because warranty not an empty sound. I?™m advanced user, I will not write about stupid problem. I think that my board has defect. Why is so hard to belive in it? I?™m not bought cheap board, I bought it new with warranty.

Thats not works! I reinstall Windows, but problem not solved. System not always initialize NVME SSD. But when 1.I unplug ssd and gpu 2. Then install GPU on PCIe and power on PC and Shut down after BIOS setup, and install NvME again and again power on pc, all works until I shut down PC.

Each time, to turn on the computer, I have to physically disconnect the video card and NVME ssd, and then, following a certain sequence, connect them back. BIOS reset does not work. It doesn't matter which operating system I use. Problem on Windows, Ubuntu, MacOS Catalina. I tried different hardware. No problem with my hardware on MOBOs: MSI z390 Tomohawk, Asus Strix z370-i, z390-i, Asrock Z370 K6. My NVME works properly, no problem when I use SATA m2 SSD. I tried Samsung 970Pro 1TB, instead my 960EVO, similar problem is. But I confirm, that all works perfect when I use GTX1080ti, and P3.30 bios. Problem starts when I sold 1080ti and bought Vega 56.