This is not virtual. This is reality. The two big beasts of the coming VR revolution are lumbering into view. It’s actually happening. By the end of April both the Oculus Rift and the HTC Vive VR headsets will be on sale. Things you can actually buy. Yes, yes, virtual reality has had several false starts. But this time, you can sense it. This time, it’s different. Well, probably. Oh, OK, nobody knows how big an impact VR is going to have in the next few years. But what I can do is help you to understand how much PC power you’re probably going need to get the most out of the new headsets.