Originally Posted by PR-Imagery
More like a high powered oversized iMac than a Mac Pro.
OSX would run on anything really.
For the usage he could go with an i5. I'd add a decent card in there, 7770 would do nicely, plus he could use it for his encodes if the software supports it.
Why lose HT?
Also if the 7790 works great on OSX side that would be the card to get.
There is a wiki page that will tell you what parts work great and whatnot.
Also Current Mac Pro's are using nehalem based chips, W3565 to be more exact (in the base unit), at only 3.2ghz. Yeah not the most impressive thing.
If you want to update OSX without really worrying about breaking it Intel is the way to go, just got to make sure you keep the bootloader updated or else the update can break that sometimes. OP just make sure you have him check to be sure he doesn't need to update anything before doing system updates, as once you reboot it is hard to fix.