Did you try installing AppleACPIPlatform Rollback from MultiBeast. My ga x58a ud7 rev 2.0 needs with Yosemite. Never did use it before.
First thing I would do is disconnect everything - SATA drives, USB flash drives, eSATA drives, etc.
With no media devices attached run memtest Prime95 for 4 or 5 iterations to check the RAM.
Then attach your OS X drive and try to get it up and running.
Problem with MacPro5,1 is the AppleTYMCEDriver.kext will hang without ECC RAM.I must say that I'm running OSX dual booting with a Windows7 OS, everyone with its own SSD hard disk. No troubles running W7 nor when I ran Maverick since last year. Don't you agree that a RAM issue is not believable?
I'm doubtful about the choice I made for my hackintosh: I defined it as a Mac Pro 5,1. Maybe is it not compatible with the hardware?
@Khan: I didn't install AppleACPIPlatform Rollback.
Bye
Rommy
Problem with MacPro5,1 is the AppleTYMCEDriver.kext will hang without ECC RAM.
I use a MacPro 4,1 system definition.
What's this mean for day-to-day use?
I'm set at MacPro 5,1 because it gave me the best benchmarks. X5650, but no ECC RAM, just the same old Corsair XMS3 1600.
For me MacPro 4,1 was worse than both 3,1 and 5,1... the latter of which seems the most stable/fast.