I need you help,
I've got a Mac Pro 1.1 (2006) 2x2,66GHZ, 6Go RAM. In first time (4 years ago) I mount a graphic card : Sapphire 5770 1Go, I could play racing games (iRacing, Assetto Corsa, PCARS) in correct conditions but not fantastic (low graphism 60-30 Fps).
Recently I install a new graphic card : Sapphire R9 390 OC 8Go. I hope real better performances but I'm really disappointed… No better FPS, impossible to increase graphism in game.
I don't know for witch reason it does work better like that. Something limit performance ? CPU frequencies ? PCI ? Other ?
I need your help.