Things continue to go from bad to worse for the box makers.

Industry tracker IDC's latest snapshot of worldwide PC sales show that there's a global slump in demand for desktops and laptops.

This is old news, but things are probably worse than you thought.

Worldwide unit shipments tumbled 8.6% during the third quarter compared to a year earlier. The plunge is more than double the 3.8% decline that IDC was forecasting for the period just two months ago.

Despite gains by Asian portable computing specialists Lenovo and Asus, the industry's in trouble. Stateside PC giants Hewlett-Packard (NYSE:HPQ) and Dell (UNKNOWN:DELL.DL) suffered through double-digit declines in worldwide shipments.

If IDC is right -- and if average selling prices don't increase -- it's highly unlikely that either company will be limited to the single-digit percentage declines in revenue that analysts have been targeting for their fiscal quarters ending later this month. Sure, they have diversified into other hardware categories and higher-margin software and services, but the efforts are unlikely to be enough.

 Company

Units

Change

HP

13.9 million

(16.4%)

Lenovo

13.8 million

10.2%

Dell

9.5 million

(14.0%)

Acer

8.4 million

(9.6%)

Asus

6.4 million

10.0%

Others

35.7 million

(12.2%)

Source: IDC.

Things are even worse closer to home, where PC units shipped have fallen 12.4% over the past year, according to IDC. Even the mighty Apple (NASDAQ:AAPL) -- which itself isn't a top five player globally, but takes the bronze domestically behind HP and Dell -- is slipping. IDC pegs Apple's unit shipments declining by 7% over the past year. Apple probably fared better internationally, but investors shouldn't expect much out of Apple's Mac and MacBook numbers when it reports later this month.

PC buffs will argue that companies and consumers are holding back ahead of Microsoft's (NASDAQ:MSFT) Windows 8 debut later this month, but there's more to this than that. The migration to tablets and smartphones as alternatives for lightweight computing is real. We're a quarter away from the sliver of folks that believe otherwise to be ultimately convinced.

 

Longtime Fool contributor Rick Aristotle Munarriz has no positions in the stocks mentioned above. The Motley Fool owns shares of Apple and Microsoft. Motley Fool newsletter services recommend Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.