I'm getting close to pulling the trigger on a Mac Pro and wanted to know if it's a good idea to either upgrade to the D500's and/or a 6-core CPU seeing that I want to drive one 4K display and possibly also use it as a server? I also wanted to know about Hyperthreading. And yes, I've google'd, etc., and basically understand what it is, but I still have a very specific question: Apple always says that OS X is designed to take advantage of all the cores and threads. Why then am I always discouraged from buying a Core i7 with Hyperthreading over the Core i5 that I currently have? Wouldn't something like Safari open faster with the additional threads? Wouldn't navigating the OS be a bit more responsive? Thanks very much!