PC Graphics

[physicsnurd]

I have an ASRock Fatal1ty X370 GAMING X motherboard and upon installing my Radeon VII the motherboard errors with a d6 (No Console Output devices are found) I have tried a single 8 pin power and an 8+6 pin. Is there some compatibility issue I am not aware of?

[goodplay]

Check your cable to monitor connection(hdmi or displayport ?).

PSU requirement 750W with 2 x 8 pin pcie connectors.

[esiotrot · Accepted solution]

Hi, there are several potential issues.

You will need 2 x 8 Pin connectors to be able to power the card. I believe min PSU is 600w but recommended is 750.

If you have 2 x 8 pin connectors and are still having these issues, are you running any raid arrays?

If so you may be experiencing an enabling of CSM on your motherboard, due to the Radeon's unusual no-UEFI support. Which is the issue I am having. If you have  UEFI reliant boot disk or array, you will be unable to boot using the Radeon VII until they release an update for the VBios. Which I hope is soon.

[goodplay]

Radeon VII Lacks UEFI Support‌

Found this, but needs confirmation if it is the new/fix vbios, amdmatt

https://www.amd.com/en/support/radeonvii-vbios-eula

[physicsnurd]

I am currently booting from a Samsung 970EVO M.2 NVMe SSD. Is it possible this is the problem? If a new vbios is needed, how can I update i if I cannot boot with the card installed?

[physicsnurd]

Also, I have ordered an 8pin to 2x 8 pin adapter, however, my understanding is the extra two pins between an 8 pin and 6 pin are just 2 extra grounds. It should still boot with an 8pin+6pin, no?

[physicsnurd]

Well, it seems using 2x8 pin rather then 1x8pin+1x6pin made the difference, works now.

[goodplay]

Not a fan of using 6 to 8 adaptors(never have).

Depending on the age/make/model of your psu, the 6 pin is probably using lighter gauge wiring.

Pulling excess power above it's rating may cook the wiring back to psu.

Why risk blowing an 800 dollar card(no warranty on psu failure). 

[physicsnurd]

It is a Corsair RM750x, 18 AWG, The wiring is not really the limiting factor in these connections, it is the plugs. the ampacity of a single 18ga stranded copper is 14A, the 6 pin has 3 of these so the wires are good for 42A or 500W @ 12v. Molex Mini fit Jr. plugs are rated to 9A per contact x3 contacts = 27A or 324 W @ 12V. This should be fine for a non overclocked card, but I would probably run separate 8-pins if I was overclocking. (I am an industrial engineer, I do this for a living)

[Matt_AMD]

Please enable CSM mode in your motherboard BIOS and check to see if you can boot the system after making this change. 

[esiotrot]

Hi Matt & goodplay,

I managed to find the link late last night, after the ASRock bios failed to allow UEFI booting, the link above https://www.amd.com/en/support/radeonvii-vbios-euladoes work however! CSM is disabled and it now boots as UEFI without any issues. (You may want to go as far as to pin that reddit post you made to the top, if you are able.)

Thank you for releasing a fix this quickly and for others in the same boat as me  -use the bios in the link above for a fix I can confirm that it does the trick.

[physicsnurd]

I checked and CSM is enabled on my motherboard. I cannot be certain it was enabled before I started, but I cleared the BIOS settings while I was trying to get the card to work and did not change any settings besides ram speed since and it still did not work. I have a 2x8 pin adapter coming to make sure it is getting all the power, but since the installation guide lists that power options are everything from 1x4pin to 2x8pin and the 1x8pin+1x6pin that I tried, I suspect that might not be the issue.

[Matt_AMD]

Each connection should have its own 6+2PIN or 8PIN connection from the 12v rail.  

[goodplay]

All good then, you don't have a $20 firecracker psu..

[physicsnurd]

Yeah, dumb thing is the 8 pin plug I have used to have another 8 pin plug on the end and I cut it off th help clean up the wiring since my rx480 only used one 8 pin...live and lern.