Installed a second GPU and system will not boot

[candymanforever]

I had a stable machine:

Gigabyte Z170X-Ultra Gaming
i7 6700k
2 x 32gb RAM
TP Link PCI wifi card
500gb SanDisk m.2 drive


Today I added a second GPU to the board and moved the Wifi card to another PCI slot.

This gave me 2 x Sapphire R9 280x cards on the machine

I get a: start[887] pci memory map failed
HID Legacy sim 2
The the system pauses for a few minutes followed by
Still waiting for root device



The system boots fine from Clover USB but just doesn't want to boot of the EFI

Does anyone know what is going on?

 

[AdamMurawski]

I have the same problem, have you solved it?

 

[B-San]

Same problem here... Updating a machine I did for a friend a couple years ago.

It was running Yosemite fine with a pair of Sapphire Radeon VAPOR-X R9 280X 3 GB's and Chimera - but now with Sierra it will only boot with one card. Oh yeah, using Clover.

Other core components in the build are as follows:

5960X

Asus X99-A

64GB of RAM - Crucial Ballistix Sport

Corsair HX1000i PSU

Corsair H100i Liquid Cooler

Samsung Pro 256GB

Any thoughts would be much appreciated!