Research firm Gartner has just released its estimates of PC shipments in the US and worldwide for Q1 2012 — it points to strong growth for Apple and HP and major declines for Acer in the US. HP and Apple were the number one and number three vendors in the US; HP shipped 4.5 million PCs, up 6.6 percent, while Apple shipped 1.6 million computers for a 3.8 percent growth rate.This far outstripped the overall US market, which actually declined 3.5 percent year-over-year to 15.5 million units. We know all about Apple's recent strength in moving units, but it looks like HP may have made the right move in not spinning off its Personal Systems Group (at least from a market leadership position). It's worth noting that these numbers do not include "media tablets" like the iPad.

The big loser in the US was Acer, who saw shipments decline nearly 26 percent compared to Q1 2011; it didn't do well in the worldwide market either, with a 9.2 percent decline year-over-year. Overall, the worldwide computer market grew 1.9 percent to 89 million units, compared to the decline seen in US shipments. HP and Lenovo dominated the worldwide market in overall shipments, though HP only showed modest growth of 3.5 percent compared to Lenovo's 28 percent growth. While the overall market only grew slightly, it still beat Gartner's expectations of a 1.2 percent decline for the quarter. Despite the unexpected growth, Gartner's analysts noted that emerging markets like India and China didn't perform as well as expected, so PC makers shouldn't depend on them to grow rapidly despite low overall penetration.