Apple increased its year-on-year PC shipment growth by 188 percent in Q1 2011, reaching fourth position in the PC manufacturer league with 8,453,980 PCs, laptops and tablets sold in the quarter. This compared to Q1 2010 sales of 2,936,310, so up 187.9 percent.

Apple’s market share rose from 3.5 percent in 2010 to 9.5 percent, according to data from Canalys today.

HP retained top spot with 16.6 percent market share, but this was down from 18.8 percent in Q1 2010. HP PC sales dropped from 15,597,690 a year ago to 14,687,210 in 2011.

Second-placed Acer also saw growth drop by 6.5 percent, and market share fall from 14.6 percent to 12.8 percent.

Dell remained ahead of Apple with 11.3 percent market share, and 2.8 percent year-on-year growth.

Apple displaced Lenovo, which saw 17 percent sales growth and a rise of 0.8 percent share but was eclipsed by Apple sales.

Canalys announced that the whole PC market grew 7 percent in Q1 2011, as the tablet market bolstered growth.

Apple’s iPad was the big winner, mainly at the expense of laptop and netbook shipments, as tablets competed for a share of consumer IT spend.

During the first quarter of this year, tablet shipments reached 6.4 million units worldwide. Apple accounted for 74 percent of these shipments, while other vendors struggled to bring competitive products to market.

Canalys expects that next quarter will see a significant change in the market, with products appearing from Acer, Asus, HP, LG and RIM BlackBerry.

Apple continued with its strategy to dominate the tablet market, with the iPad or iPad 2 available in 59 markets by the end of Q1.

Ironically a combination of strong Q4 sales and the announcement of the iPad 2’s launch across major markets at the end of March contributed to Apple’s iPad shipments being down 31 percent sequentially.

The full impact of the iPad 2 launch will not register until subsequent quarters, as Apple gets the product into the hands of consumers. While tablet sales continued to lift Apple’s results, PC vendors with a focus on the consumer netbook and laptop market, such as Acer and Asus, did not fare so well.

Overstocked retail channels and unsteady consumer confidence in major European countries and the United States cast a shadow over the potential for notebook market growth during the remainder of 2011.

“Taking into consideration the iPad’s ‘halo effect’ on the company’s other products, Apple has grown considerably in most markets worldwide,” said Canalys analyst Tim Coulling.

“As the iPad 2 and its competitors continue to roll out, we expect pad sales to propel PC market growth for the rest of the year.”