There are a few theories on why PC sales have been slumping. Gartner's Kitagawa blames the obvious: low-priced tablets. "We are seeing the PC market reduction directly tied to the shrinking installed base of PCs, as inexpensive tablets displace the low-end machines used primarily for consumption in mature and developed markets," Kitagawa said. "In emerging markets, inexpensive tablets have become the first computing device for many people, who at best are deferring the purchase of a PC. This is also accounting for the collapse of the mini notebook market."
Gartner also cited Intel's launch of Haswell processors for hurting sales because it forced PC makers to cut shipments to make room for new systems running Intel's latest microprocessors. This is a theory IDC also bolstered: "Vendors and regions seemed to be focused on inventory reduction during the second quarter, which could reflect planned launches of new models as well as lower inventory going into the second half of the year."