mac wont boot when pc gpu is plugged into mb power

[PhoenixMac]

When I unplugg my pc vid card 5770 i can boot to mac but when i plug it in the power port on motherboard i can only bootcamp to windows is this normal?

kind of a hassle everytime i want to play games because i have to shut down then plug in vid card to crossfire

 

[ActionableMango]

Actual people who know what they are talking about (not me), will probably need more details about your hardware.

 

[PhoenixMac]

mac pro 5,1 came with 5770 slot 1
i added sapphire 5770 into slot 3
bought mb 6pin power cord from owc

when both cards are plugged into motherboard i can bootcamp to windows but when i try to boot osx10.6.4 i get to the apple and then the screen goes darker and i get a hold the power button to turn off mac and press it again to boot.

 

[alust2013]

From what I have heard that is normal, as the PC card does not work with the EFI on the Mac Pro for booting OS X

 

[CaptainChunk]

Hmmmm...maybe try flashing the PC card with an EFI64 ROM? It's possible that the machine might be trying to initialize both cards while booting into OS X. What's strange though is that I used to boot OS X with a 2600XT (main card) and 8800GTS (secondary PC-only card in Slot 2) just fine. But I eventually ended up flashing the 8800 to use as my main anyway.

Perhaps some of the GPU experts here can chime in.

 

[Cindori]

osx is trying to initialize pc card but fails because..its a pc card. = kernel panic.
flash it. netkas forum.