Hello all !
I got an "official" MacPro4,1 (2x2,26 GHtz Nehalem)
with Mac OS X "El Capitan" 10.11.2
and also Windows 8 on an Bootcamp partition.
I just bought a SAPPHIRE AMD VAPOR-X R9 270X 2G D5 graphic card.
which seem to work fine on windows
on Mac it is reconnized as "AMD Radeon HD 7xxx 2048 Mo" but relatively work
exept on System information when I click on PCI I got a message say an error occured gathering PCI devices informations.
The main problem is it start up with black screen and go directly to my user desktop without any gray apple logo screen and progress bar.
if it is only this, it is ok for me. but when I try to boot with option (to choose which System to boot to) or any other booting option
( Apple + R = to go to Disk Utilities or even Apple + S = for single user terminal boot)
it didn't work at all, I got a black screen. nothing can be done or happening.
So I'm stuck with my original boot system (OS X or Windows)
I read at little about Clover but I'm not sure it is the solution as I am on a real Mac Pro not a Hackintosh.
Sorry cause I am a newbie concerning all these matters...
I thanks you very much in advance for any of your help.