I saw a short post about this on Bit-Tech last night, & was very intrigued. I can tell you right now that every programmer on the planet is going to be frothing at the mouth at the possibilities...

"It's well known that two CPUs - whether two separate processors or two cores on the same die - don't generate, clock for clock, double the performance of a single CPU. However, by making the CPU once again appear as a single logical processor, AMD is claimed to believe it may be able to double the single-chip performance with a two-core chip or provide quadruple the performance with a quad-core processor.