IDC and Gartner have released fresh reports detailing the state of the PC industry. According to both research houses, global PC shipments in the second quarter grew by 2.3% to 2.6% on-year, depending on whose figures you believe. During that same period, US-specific shipments have dropped by 4.2% to 5.6%, but they've increased between the first and second quarter of 2011. Both outfits believe US sales have declined on-year because of increased interest in tablets such as the iPad and waning interest in netbook-like devices.

Based on IDC's stats, HP is still the largest PC vendor in the US (and worldwide for that matter) with a stateside market share of 26.3%. Dell follows at 22.2%, Apple nudged its way to third with 10.7%, Toshiba is fourth with 9.1% and Acer ranked last in the US, representing 8.5% of the market. Gartner reports the same overall standings with pretty similar figures. Acer's performance is potentially the most noteworthy stat displayed on the charts as the company's market share has fallen by 20% to 25% in the US and worldwide.

IDC's top five US PC vendors, second quarter 2011

It feels like just yesterday Acer was plowing its way to the top of the charts, taking Dell's second place position and threatening HP's top spot in global PC shipments. Now it sits more than a percentage point behind Lenovo in fourth position. Gartner said Acer's low-price, high-volume business model is no longer effective, but the firm didn't elaborate. The Taiwanese system builder has experienced much turbulence in the last year, having ousted former CEO Gianfranco Lanci and splitting into two separate business groups.