I just got my Sapphire RX 460 4gb OC plugged in to my 5,1 Mac Pro. This is my first time swapping gfx cards so I'm totally new to this. Here's my situation - maybe you can give me some advice: Removed the 5770. Installed the RX 460 Rebooted computer - no boot screen. Desktop shows up shortly afterwards. About this Mac shows: AMD R9 xxx 4096 MB System Report > PCI shows: "There was an error while gathering PCI device information" which is unsettling. When the computer boots, I can see the 460's fans spin up, but they come to a halt when the computer reaches the desktop. If I spin up the fans manually with iStat they still do not spin up. What am I doing wrong, or has everything been done correctly? The fans sitting silently make me nervous, and the fact that I don't have PCI information anymore also is unsettling. EDIT: Quick revision - I just opened one of the few games I have, Civ VI, and let it run a benchmark, which seemed to do decent - more importantly, I cracked the case open and took a look at the fans, and they spun up in the game, so that's reassuring. Still wish I could have the PCI information, since I use it for my ACHI blade as well - is this a cosmetic issue which is fixed if I change the kext information, or does that strictly impact the computer displaying RX 460 instead of R9?