AMD's CEO Hector Ruiz admitted in an interview that their upcoming Barcelona processor had many more technical glitches than they hoped, and that this caused several delays:
It's awfully complicated. We're doing something that nobody has ever done. As strong as our competitor is, they have not done a quad core on a chip (four chip cores, or brains, laid out on a single piece of silicon instead of on two pieces attached together). . . . Every time we ran into a gotcha (or technical glitch), it created a six-week or so hole in the schedule as we went back and fixed it. We hoped we wouldn't get many of those, but in the Barcelona case, we got more than we thought. By the time we got through fixing them all, we were six months-plus late from where we originally wanted to be.