asus crosshair VI hero.. graphics card change threw q-code 8 error..

[gsxr1000]

hi all,

I was using sapphire r9 290 tri-x with asus rog crosshair VI hero without any problems. then I found a sapphire rx 590 nitro se and install it to this mainboard. I made a fresh windows 10 setup, everything went ok. then I login to windows and after 3 or 4 minutes from login monitor went blank and mainboard threw q-code 8 error. when I login windows same thing happened.

what I did to get rid of q-code 8;

- fresh windows install with rx 590.
- changing power plan to performance from ryzen balanced.
- downgrade bios to 6401 for changing psu supoort idle control option to typical current idle from bios. with bios 6401 it threw code d3.
- changing video card bios switch right to left.
- changing bios pcie settings to gen1, gen2 and gen3
- installing rx 590 to pcie x8 slot
- changing power supply
- checking ram with memtest86. they are all passed all tests.

none of the above worked.

I also installed rx 590 nitro se to my other pc which has gigabyte 990fxa-ud3 mainboard and it worked flawlessly. there is a conflict between crosshair IV and rx 590 but I couldn't find what it is?

what should cause q-code 8 error?

some info about my pc;

cpu : ryzen 7 1800x
ram : Kingston 16GB (2x8GB) 3200MHz CL16 HyperX Predator RGB DDR4 HX432C16PB3AK2/16
psu : seasonic x-series 850 watt gold
ssd : memoright ftm 120 gb - windows 10
hdd : western digital black 2 TB
os version : 21H1
os build : 19043.928

 

[gsxr1000]

update;

I installed windows 11, same q-code 8 error again.