Upgrading from Mountain Lion to Yosemite - is it possible?

[meet.nick]

Hello everyone,

My system is a Mac Pro 1,1 with Mountain Lion 10.7.5 and the following specs:
Processor 2 x 2.66 GHz Dual-Core Intel Xeon
Memory 17 GB 667 MHz DDR2 FB-DIMM
Graphics ATI Radeon HD 5770 1024 MB
Hard disks 1 SSD 250 GB and 2 RAID 1TB each

I tried the method in post 3 of this thread but I am unable to boot from the USB stick inspite of adding the following lines:
<key>GraphicsEnabler</key>
<string>Yes</string>
<key>PCIRootUID</key>
<string>1</string>

Could someone help me please?

 

[6Dwanderer]

I know this an old thread but my question is about the post install process. Assuming the install of Yosemite goes perfectly over my previous 10.8.4 install and successfully boots to Yosemite. Am I then able to run Migration assistant to reinstall the apps and system files from my previous bootable SSD with all my apps (From a time machine back up that lives on another HDD in the Hackintosh)? Has anyone had good/bad experiences with migration assistant in this capacity? Not sure if it's a big deal for the Hackintosh to restore a 10.8.4 install configuration to a 10.10.

Thank you for your help.