I ve a dell optiplex 3020 MT and i got a brand new rx 570 4gb mining edition. i replaced the psu to a thermaltake 700w and i use a 24 pin to 8 pin connector for the the motherboard . My computer just works fine but when the GPU is installed the computer turns on, CPU fan is spinning / GPU fans too /the lights are on but no display, nothing shown on the screen. i put the the VGA cable to the convertor and then i plug it into the GPU. the computer turns on but no boot and nothing shown on the screen again . and when i plug the VGA cable into the motherboard it works and i can see the GPU information on CPUZ. .i updated the bios to the latest version that i found on dell website, and put the boot mode on UEFI . i put secure boot OFF and legacy option roms ON? but the same thing happened. so what other ways i can try ? ? Note i m plugging the 8 in the GPU and every other cable is plugging properly.
Secure Boot must be OFF with CSM Legacy Option roms ON in bios.
Even with that I doubt that it works due to insufficient power on the 3.3v / 5v rails combined.
You also may have a fake card.
EVGA 750B1 or 700B1 works but B2 BQ G2 W1 N1 does not for the exact power issue.
This is not the Joe's Crab Shack Fake RX570 support board.
R series cards require secure boot OFF in bios.
Not using specific adapter and power supply is also an issue.