6 months is putting it mildly. I would say a year or two personally.
I don't think they're that far behind. Bulldozer/Piledriver CPUs aren't up there with the i7's, but on a price/performance scale they're punching their weight. The top end Bulldozer/Piledriver competes with an equivalent price high-end Core i5, and they're very quick in parallel tasks. They just suck at single-threaded tasks. Steamroller was supposed to be their saviour next year, with rumours like a 25% speed bump in single-thread performance, but that's been pushed back to 2014, which could be a fatal mistake.
AMD's problem is that they bet on high parallelism being a hot thing, and they bet wrong. That and the ATI purchase, and the Intel antitrust thing.