I've reached my limit with Windows 8 and my self built PC. Starting a month ago it's been getting more and more unreliable and I'm just done with it. Current specs on the PC: Core i7 2600k 16GB DDR3 GTX470 I'm thinking about picking up a friends Mac Pro, 2.93ghz Nehalem with Radeon 4870. I'll be moving over my SSDs and drives. Questions: My main heavy lifting on the PC is Lightroom 4 and 5. How much slower will the Mac Pro compared to my PC? Will I be able to move my Corsair XMS3 DDR3 RAM to the Mac Pro? What sort of cage will I need for my 2 SSD drives that are 2.5"? How much faster will XCode be than my Retina 13 2.5ghz? Is the CPU upgradeable?