Hey guys,
had the same problem with my build (gtx770 2gb, i7 IvyBridge, ga-z77-UD5h)
I installed 10.10 and updated directly to 10.10.3, still no luck.
Then i tired MacPro 3,1 smbios,
UseKernelCache=No and IGPEnabler=No and IT WORKED!!!!
Now I have my Hack working again. Since 10.10.3...