Why FXF Radeon R9-280X NOT working on MacPro 3.1 with Yosemite 10.10.1 ?
I have a MacPro 3.1 with 2 Quad Cores 2,8Mhz. I removed the hard drive and replaced it with a 250Go Samsung EVO SSD for system, a 1To SSHD (that is the latest hard drives with SSD's speed) as second drive, i added 8Go of RAM, an INATECK eSATTA card to have USB 3.0 and 2 MSI Geforce GT-610 of 2G of VRAM. The computer became pretty reactive and i could run Final Cut Pro X with my 4000 and more pluggings with no strain. The only hic was that as a SATTA 2 computer, i'm not getting the full speed from the SSD and the SSHD (half of their speed in fact but still much better than a normal hard drive) because they are SATTA 3 but everything was working pretty well (without boot screen because of the graphic cards).
I decided to replace the 2 MSI GT-610 by one better card and i invested in a FXF R9-280X TDBD Black Edition of 3Go of VRAM. I had to use an external 300W power supply unit from a old PC. Unfortunately, the computer won't start at all. I put back the stock MacPro poor default card just to see what is going on so i got he boot screen, the charging line appears but the computer freezes before the login window.
Can somebody tell me how to have this FXF R9-280X TDBD Black Edition to work on the MacPro ?