I read the post related to this upgrade but feel a bit overwhelmed as I am not super technical. I have a few basic questions to help me decide whether to commit or not. First, my system is a 2007 MacPro 2,1 with 8 core, 16gb RAM, dual-display original graphic card and 4 internal Sata drives. Currently running Lion 10.7.5 which is the last possible Apple-supported upgrade. I also own a 2012 iMac currently running 10.10.1. I do not need advanced graphics prcoessing as this is an audio recording machine for Logic Pro X only. My questions: 1. Do I need to buy a new graphics card for the upgrade to work at all? If not, do I only lose the boot display? if yes, are my two options depending on whether I want to see the boot display or not? If I need a new card and have a budget of $250, what is the cheapest card I should consider? Does it require some sort of flashing no matter what, or only if I want to see the boot screen? 2. As far as the overall upgrade process, once #1 has been resolved, is it easier to do the upgrade from my iMac running Yosemite? I understand that there are 2-3 options to to this but still overall confused between the different approaches. 3. Would susbequent Yosemite upgrades require any touching-up, or it would be 100% seamless? I'd be happy to stay at 10.10.1 forever in any case. I realize this is repetitive, but what is the the easiest path to get this done as the long technical threads are a bit overwhelming?