Hi everyone, First of all I apologize if there is similar thread, I tried to google my problem but I didn't found anything. I sucessfully installed Mavericks on my AMD PC which has : FX 8320 GIGABYTE 990XA-UD3 and Asus GTX 670. I noticed something wears - in Cinebench in Windows GPU result is 90 fps and on OSX its 45. Then I tried using AMD HD6850 and results were interesting - 75 in Windows and 71 in OSX , so it's not AMD kernel problem. I tried latest NVIDIA drivers for 10.9.5 but it didn't fixed the problem. Some people said that changing smbios from 3,1 to 4,1 or 5,1 would fix the problem, so I tried that, but it didn't help. Maybe it's DSTD problem, i'm bad at that stuff so i think I got that thing wrong. I'm uploading my IOReg, maybe someone could figure out how to make PCIE work in 2.0 mode.
WideKing’s Mac Pro.zip