Worldwide PC shipments jumped at least 20 percent during the second quarter, according to two separate reports from IDC and Gartner.

The global PC market increased 22.4 percent this past quarter according to IDC, though growth in the United States was slightly behind projections.

Gartner, meanwhile, saw a 20.7 percent increase during the same time period, up slightly from the company's 19.3 percent projection.

The two firms disagreed, though, as to whether Acer or Dell took the second and third spots for U.S. market share behind Hewlett-Packard.

IDC Data

Worldwide, PC shipments exceeded expectations, IDC said. This was largely due to businesses that purchased replacement machines. Portable PC sales among consumers trailed forecasts.

"The PC market remains robust, and in a recovery phase, despite challenges to a broader economic recovery, such as slow job growth and a more conservative outlook in Europe and Asia/Pacific," Jay Chou, research analyst with IDC's Worldwide Quarterly PC Tracker, said in a statement. "The factors which led to the recent PC rebound – an aging commercial installed base, a proliferation of low-cost media-centric PCs, and low PC penetration through much of the world – remain key drivers going forward."

Growth in consumer spending, meanwhile, has slowed somewhat, though that was expected, said Bob O'Donnell, IDC's vice president for clients and displays.

"We expect consumer activity to remain healthy, but gradually slow through the end of the year, while commercial market growth will be more stable, reflecting a planned replacement cycle over the next several years."

IDC put HP as the top vendor for worldwide shipments, with 18.1 percent of the market. That was followed by Dell with 13 percent and Acer with 12.6 percent.

In the U.S. alone, the market saw small growth quarter-over-quarter and a 12.6 percent jump year-over-year. There was "some healthy PC refresh activity," IDC said, but people are still being cautious due to the economy.

HP was also tops in the U.S. with 25.7 percent of the market, followed by Dell at 24 percent, and Acer at 11 percent.

Gartner Weighs In

Gartner saw similar trends. Worldwide PC shipments reached 82.9 million during the second quarter, slightly above Gartner's projections.

"The preliminary second quarter results indicate ongoing improvement of the PC market, and it marks the third consecutive quarter of double-digit growth on a year-over-year basis," Mikako Kitagawa, principal analyst at Gartner, said in a statement. "End-user spending grew approximately 13 percent in the second quarter. Average selling prices (ASPs) continue to decline, but at a much slower rate compared with the last two years."

While mini-notebook shipment growth still exceeded the growth rates of the overall mobile PC market, mini-notebook growth slowed to the low 20 percent range. This signals that the devices are entering a mature growth stage, Kitagawa said.

Broken out by manufacturer, HP maintained its worldwide lead in PC shipments with 17.4 percent of the market, though its growth rate was below the industry average, Gartner said.

Gartner disagreed slightly with IDC over the second and third spots for global market share. Gartner put Acer in second with 13 percent, followed by Dell with 12.4 percent, compared to IDC, which had Dell in second with 13 percent and Acer in third with 12.6 percent.

In the U.S., HP was still the top PC vendor, with 25.7 percent of the market. That was followed by Dell with 23.7 percent, Acer with 11.3 percent, Apple with 9.8 percent, and Toshiba with 8.7 percent, Gartner said.