Check your Motherboard bios is up to date and using the latest revision.
I am having the same issue. Like a bunch of people if i google it. But no exact solution for a problem.
I have done my build a month ago:
I7 6700 3.4ghz
Asrock z170 extreme4 motherboad
16gb ddr4 ram
Corsair 650 gold fully modular psu
samsung 840 500gb ssd
Sapphire rx 480 4gb
New Lg 23 inch freesync monitor
When I connect the monitor to motherboard's hdmi, it works like a charm.
When I plug in the rx 480, it does get recognized by a monitor, so it goes to sleep.
All fans, cpu and rx 480 fans spining and powered, just no signal.
I have tried everything possible from forum suggestions and so on.
The only temporary (but not a proper) solution to get it to work is:
Unplug rx 480, Connect through mobo's hdmi port, go into bios( or in my case uefi) by pressing F2 after restart,
set the primary Gpu the Onboard one, Put the rx 480 in, but keep using mobo's hdmi connection,
now when in windows 10 download and install amd driver for rx 480,. Shutdown. Plug in hdmi cable to rx 480 and turn on pc.
It will skip (won't show) motherboard logo/ uefi/bios screen , screen will go black, but after few seconds picks up a signal and boots into windows.
When I can use it and play games normally. But after few days I encounter a problem again, it wont go into windows anymore, so have to repeat a process ,by deleting gpu driver. If i set up the primary gpu as a pcie one and/or disable onboard together, it wont boot at all with rx 480 or onboard gpu, so I have to reset cmos to be able to use pc again.
The most common suggestion is to update the bios. I have done it ,but no luck. Still the same. This issue still exists if I look up online and no solution found.
And if someone says use bios switch on the rx480, it is not legacy bios/uefi switch, but gives overclocked speeds( faster).
So, what could it be? Too many people having the same issue, so it would not be correct to say that rx480 is not compatible with motherboard(I have checked on pcpartpicker) it said all parts are compatible for my build.
I am very close to sending the gpu back to retailer and getting nvidia card.
Any solution here?
have you tried plugging the card into a different computer to make sure it works? if it has the same problem on a different motherboard then the card is bad. if it doesn't work on your computer, it is likely the bios on the mobo isn't working with it.
i have an msi 480 8gig vram and had that problem on a different mobo, i plugged it into a different computer and it worked fine, then i figured out it had to be the bios on mobo wasn't recognizing it. so i flashed bios and now it works just fine.
i know you said you flashed bios, but i'd try again. make sure the when you flash it, the bios has code that will recognize amd gpu's.
Most hd7xxx series ran with legacy bios, the rx400 series use uefi bios.
Change mobo bios setting to run card in uefi mode.
Could you guide me through the step changing bios setting to run card in uefi mode? I do not see this option... Thanks
Yours is a different problem as your card does work for a time.
I don't have a 4xx card, amdmatt would have a better idea of suggestions for your problem.
have you plugged the card into a different mobo to make sure the card works? if it works in the other computer then it is the bios of your computer that is causing it not to boot up. i'd just flash the bios. when you dl the updated bios, make sure it has code that recognizes amd cards.