Although a historic downturn in PC shipments has made headlines since April, "peak PC" -- the moment when personal computers crested -- was two years ago, according to data from researcher IDC. In the third quarter of 2011, global PC shipments totaled 96.1 million, slightly more than the following quarter's 95.8 million, IDC said. But shipments declined 4 percent in 2012 and are headed for an even larger dip of 8 percent, perhaps more, in 2013.