China has passed an important technological milestone: It became the world's biggest consumer of PCs in the second quarter, according to new market research by IDC.

Computer makers shipped about 18.5 million PCs in China in the second quarter, compared with 17.7 million in the U S.

The U S is still expected to be the world's largest market for the full year, but it will likely lose that distinction next year. IDC forecasts that 85.2 million PCs will be shipped in China compared with 76.6 million in the U.S. in 2012.

"China's lead in the PC market is a huge shift that reflects the rising fortunes of emerging markets as well as the relative stagnation of more mature regions," said Loren Loverde, an IDC vice president. "While the immediate economic circumstances in the US and other markets had a significant impact on the timing of China's move to the lead, they have not changed the trend, but accelerated it."

China's PC market is growing at a time that the U S and European PC markets are contracting, the result of economic anxieties and competition from smart phones and tablet computers such as Apple's iPad.

China already has the world's largest Internet population, having surpassed the U.S. in 2008.Market research numbers such as IDC's are imprecise measurements. IDC's figures refer to shipments to distributors and end users, so they include PCs that may ultimately not have been sold. However, they are often the best public gauge about the strength of the spread of technology.