Pretty boring and irrelevant article IMHO... also, what the heck do they mean by this?
However, users with dual-core PCs may notice a performance boost with Vista when they're multitasking, because Vista can take advantage of dual cores to run separate processes, something that XP can't do. So if you have a dual-core PC and you frequently run multiple programs simultaneously, you will lose the performance improvement that Vista can bring.
Even NT4 supports multi-CPU systems. And multitasking isn't done per-process anyway, it's done per-thread.
Microsoft also claims that multimedia will run better in Vista than XP because Vista can give streaming audio and video priority over other processes so that they won't be interrupted.
That sounds a bit silly as well - you can already manually (or with whatever tool) raise your media player process priority.