IDC is optimistic, and sees this as a sign that the computer business is catching a break now that growth in smartphone and tablet sales is slowing down. Gartner, however, isn't quite so cheerful. It sees the drop as evidence of "stagnation" and the shift in just how people buy PCs. While there's fast growth among enthusiasts (think gamers and power users), that's more than offset by the majority of 'casual' buyers who are holding off as they spend more time on their phones. If you only occasionally use your PC, you're more likely to wait longer before replacing it.

There has been a bit of a shakeup among the leaders. While Lenovo, HP and Dell are still atop the ranks and gaining share, Apple appears to have made a slight recovery thanks to pent-up demand for a new MacBook Pro. The biggest losers were Acer, ASUS and a slew of smaller manufacturers.

The estimates also represent a milestone that the PC world would likely rather forget. It's the fifth year in a row that shipments are down overall, at roughly 6 percent for both Gartner and IDC. Although there are signs that the market is leveling off, the data casts doubt on previous claims that the computer business is just facing an extended rough patch due to smartphones and slow-to-upgrade corporate customers. This sluggishness increasingly looks like the new normal, and there's no obvious point at which demand is likely to bounce back.